diff --git a/web/src/components/PageStub.tsx b/web/src/components/PageStub.tsx
deleted file mode 100644
index 6ce21ba..0000000
--- a/web/src/components/PageStub.tsx
+++ /dev/null
@@ -1,13 +0,0 @@
-import type { ReactNode } from 'react'
-
-/** Placeholder page scaffolding used until each feature issue fills these in. */
-export function PageStub({ title, children }: { title: string; children?: ReactNode }) {
-  return (
-    <section>
-      <h1 className="text-2xl font-semibold tracking-tight">{title}</h1>
-      <p className="mt-2 text-sm text-muted">
-        {children ?? 'Placeholder — this page arrives in a later issue.'}
-      </p>
-    </section>
-  )
-}
diff --git a/web/src/components/gardens/DeleteGardenModal.tsx b/web/src/components/gardens/DeleteGardenModal.tsx
index 195552b..c187c89 100644
--- a/web/src/components/gardens/DeleteGardenModal.tsx
+++ b/web/src/components/gardens/DeleteGardenModal.tsx
@@ -1,42 +1,22 @@
-import { useState } from 'react'
-import { Modal } from '@/components/ui/Modal'
-import { Alert } from '@/components/ui/Alert'
-import { Button } from '@/components/ui/Button'
-import { errorMessage } from '@/lib/api'
+import { ConfirmModal } from '@/components/ui/ConfirmModal'
 import { useDeleteGarden, type Garden } from '@/lib/gardens'
 
 /** Confirmation dialog for deleting a garden (and everything in it). */
 export function DeleteGardenModal({ garden, onClose }: { garden: Garden; onClose: () => void }) {
   const deletion = useDeleteGarden()
-  const [error, setError] = useState<string | null>(null)
-
-  async function onConfirm() {
-    setError(null)
-    try {
-      await deletion.mutateAsync(garden.id)
-      onClose()
-    } catch (err) {
-      setError(errorMessage(err, 'Could not delete the garden.'))
-    }
-  }
-
   return (
-    <Modal title="Delete garden" onClose={onClose} busy={deletion.isPending}>
-      <div className="flex flex-col gap-4">
-        <p className="text-sm text-muted">
-          Delete <span className="font-medium text-fg">{garden.name}</span> and everything planned in it?
-          This can't be undone.
-        </p>
-        {error && <Alert>{error}</Alert>}
-        <div className="flex justify-end gap-2">
-          <Button type="button" variant="ghost" onClick={onClose} disabled={deletion.isPending}>
-            Cancel
-          </Button>
-          <Button type="button" variant="danger" onClick={onConfirm} disabled={deletion.isPending}>
-            {deletion.isPending ? 'Deleting…' : 'Delete'}
-          </Button>
-        </div>
-      </div>
-    </Modal>
+    <ConfirmModal
+      title="Delete garden"
+      confirmLabel="Delete"
+      busyLabel="Deleting…"
+      errorFallback="Could not delete the garden."
+      onConfirm={() => deletion.mutateAsync(garden.id)}
+      onClose={onClose}
+    >
+      <p className="text-sm text-muted">
+        Delete <span className="font-medium text-fg">{garden.name}</span> and everything planned in it?
+        This can't be undone.
+      </p>
+    </ConfirmModal>
   )
 }
diff --git a/web/src/components/gardens/LeaveGardenModal.tsx b/web/src/components/gardens/LeaveGardenModal.tsx
index 85c9dce..5ccb540 100644
--- a/web/src/components/gardens/LeaveGardenModal.tsx
+++ b/web/src/components/gardens/LeaveGardenModal.tsx
@@ -1,8 +1,4 @@
-import { useState } from 'react'
-import { Modal } from '@/components/ui/Modal'
-import { Alert } from '@/components/ui/Alert'
-import { Button } from '@/components/ui/Button'
-import { errorMessage } from '@/lib/api'
+import { ConfirmModal } from '@/components/ui/ConfirmModal'
 import { useMe } from '@/lib/auth'
 import type { Garden } from '@/lib/gardens'
 import { useRemoveShare } from '@/lib/shares'
@@ -12,36 +8,26 @@ import { useRemoveShare } from '@/lib/shares'
 export function LeaveGardenModal({ garden, onClose }: { garden: Garden; onClose: () => void }) {
   const me = useMe()
   const remove = useRemoveShare(garden.id)
-  const [error, setError] = useState<string | null>(null)
-
-  async function onConfirm() {
-    if (!me.data) return
-    setError(null)
-    try {
-      await remove.mutateAsync(me.data.id)
-      onClose()
-    } catch (err) {
-      setError(errorMessage(err, 'Could not leave the garden.'))
-    }
-  }
-
   return (
-    <Modal title="Leave garden" onClose={onClose} busy={remove.isPending}>
-      <div className="flex flex-col gap-4">
-        <p className="text-sm text-muted">
-          Leave <span className="font-medium text-fg">{garden.name}</span>? You'll lose access until the owner
-          shares it with you again.
-        </p>
-        {error && <Alert>{error}</Alert>}
-        <div className="flex justify-end gap-2">
-          <Button type="button" variant="ghost" onClick={onClose} disabled={remove.isPending}>
-            Cancel
-          </Button>
-          <Button type="button" variant="danger" onClick={onConfirm} disabled={remove.isPending || !me.data}>
-            {remove.isPending ? 'Leaving…' : 'Leave'}
-          </Button>
-        </div>
-      </div>
-    </Modal>
+    <ConfirmModal
+      title="Leave garden"
+      confirmLabel="Leave"
+      busyLabel="Leaving…"
+      confirmDisabled={!me.data}
+      errorFallback="Could not leave the garden."
+      onConfirm={async () => {
+        // The button is disabled without a current user; throw rather than
+        // silently resolve (which would close the dialog as if it had worked) if
+        // that guard ever drifts.
+        if (!me.data) throw new Error('Not signed in.')
+        await remove.mutateAsync(me.data.id)
+      }}
+      onClose={onClose}
+    >
+      <p className="text-sm text-muted">
+        Leave <span className="font-medium text-fg">{garden.name}</span>? You'll lose access until the owner
+        shares it with you again.
+      </p>
+    </ConfirmModal>
   )
 }
diff --git a/web/src/components/layout/AppShell.tsx b/web/src/components/layout/AppShell.tsx
index 7e525df..76973e9 100644
--- a/web/src/components/layout/AppShell.tsx
+++ b/web/src/components/layout/AppShell.tsx
@@ -39,14 +39,19 @@ export function AppShell() {
   // so the '/gardens' list itself still shows the bar.
   const inEditor = !!matchRoute({ to: '/gardens/$gardenId', fuzzy: false })
   const inPublicGarden = !!matchRoute({ to: '/g/$token', fuzzy: false })
-  const showBottomNav = !!user && !inEditor && !inPublicGarden
+  // A canvas route wants the whole width — the garden editor is squeezed by the
+  // max-w-5xl reading measure the other pages use (#107).
+  const canvasRoute = inEditor || inPublicGarden
+  const showBottomNav = !!user && !canvasRoute
 
   const visibleSections = sections.filter((s) => !s.adminOnly || user?.isAdmin)
 
   return (
     <div className="flex min-h-full flex-col">
       <header className="sticky top-0 z-20 border-b border-border bg-surface/90 backdrop-blur">
-        <nav className="mx-auto flex max-w-5xl items-center gap-4 px-4 py-3">
+        {/* The bar matches the content width below: constrained on reading pages,
+            edge-to-edge on the canvas routes so the brand aligns with the editor. */}
+        <nav className={cn('flex items-center gap-4 px-4 py-3', canvasRoute ? '' : 'mx-auto max-w-5xl')}>
           <Link to="/gardens" className="text-lg font-semibold text-accent-strong">
             🌱 pansy
           </Link>
@@ -87,7 +92,10 @@ export function AppShell() {
 
       <main
         className={cn(
-          'mx-auto w-full max-w-5xl flex-1 px-4 py-6',
+          'w-full flex-1 px-4 py-6',
+          // Constrain the reading pages to a comfortable measure; the canvas
+          // routes go edge-to-edge so the garden gets the whole screen.
+          !canvasRoute && 'mx-auto max-w-5xl',
           // Clear the fixed bottom bar on mobile so content isn't hidden behind
           // it. The 3.5rem must match BottomNav's h-14 (kept adjacent below).
           showBottomNav && 'pb-[calc(3.5rem+env(safe-area-inset-bottom))] md:pb-6',
diff --git a/web/src/components/plants/DeletePlantModal.tsx b/web/src/components/plants/DeletePlantModal.tsx
index 69e1798..21805b5 100644
--- a/web/src/components/plants/DeletePlantModal.tsx
+++ b/web/src/components/plants/DeletePlantModal.tsx
@@ -1,46 +1,26 @@
-import { useState } from 'react'
-import { Modal } from '@/components/ui/Modal'
-import { Alert } from '@/components/ui/Alert'
-import { Button } from '@/components/ui/Button'
-import { errorMessage } from '@/lib/api'
+import { ConfirmModal } from '@/components/ui/ConfirmModal'
 import { useDeletePlant, type Plant } from '@/lib/plants'
 
 /**
  * Confirmation dialog for deleting a custom plant. A plant still used by
- * plantings is refused by the server (409 PLANT_IN_USE); we surface that
- * message inline rather than pretending it worked.
+ * plantings is refused by the server (409 PLANT_IN_USE); ConfirmModal surfaces
+ * that message inline rather than pretending it worked.
  */
 export function DeletePlantModal({ plant, onClose }: { plant: Plant; onClose: () => void }) {
   const deletion = useDeletePlant()
-  const [error, setError] = useState<string | null>(null)
-
-  async function onConfirm() {
-    setError(null)
-    try {
-      await deletion.mutateAsync(plant.id)
-      onClose()
-    } catch (err) {
-      setError(errorMessage(err, 'Could not delete the plant.'))
-    }
-  }
-
   return (
-    <Modal title="Delete plant" onClose={onClose} busy={deletion.isPending}>
-      <div className="flex flex-col gap-4">
-        <p className="text-sm text-muted">
-          Delete <span className="font-medium text-fg">{plant.name}</span> from your catalog? This can't be
-          undone.
-        </p>
-        {error && <Alert>{error}</Alert>}
-        <div className="flex justify-end gap-2">
-          <Button type="button" variant="ghost" onClick={onClose} disabled={deletion.isPending}>
-            Cancel
-          </Button>
-          <Button type="button" variant="danger" onClick={onConfirm} disabled={deletion.isPending}>
-            {deletion.isPending ? 'Deleting…' : 'Delete'}
-          </Button>
-        </div>
-      </div>
-    </Modal>
+    <ConfirmModal
+      title="Delete plant"
+      confirmLabel="Delete"
+      busyLabel="Deleting…"
+      errorFallback="Could not delete the plant."
+      onConfirm={() => deletion.mutateAsync(plant.id)}
+      onClose={onClose}
+    >
+      <p className="text-sm text-muted">
+        Delete <span className="font-medium text-fg">{plant.name}</span> from your catalog? This can't be
+        undone.
+      </p>
+    </ConfirmModal>
   )
 }
diff --git a/web/src/components/plants/DeleteSeedLotModal.tsx b/web/src/components/plants/DeleteSeedLotModal.tsx
index 5d7dc00..c535435 100644
--- a/web/src/components/plants/DeleteSeedLotModal.tsx
+++ b/web/src/components/plants/DeleteSeedLotModal.tsx
@@ -1,8 +1,4 @@
-import { useState } from 'react'
-import { Alert } from '@/components/ui/Alert'
-import { Button } from '@/components/ui/Button'
-import { Modal } from '@/components/ui/Modal'
-import { errorMessage } from '@/lib/api'
+import { ConfirmModal } from '@/components/ui/ConfirmModal'
 import { formatQuantity, useDeleteSeedLot, type SeedLot } from '@/lib/seedLots'
 
 /**
@@ -12,39 +8,23 @@ import { formatQuantity, useDeleteSeedLot, type SeedLot } from '@/lib/seedLots'
  */
 export function DeleteSeedLotModal({ lot, onClose }: { lot: SeedLot; onClose: () => void }) {
   const del = useDeleteSeedLot()
-  const [error, setError] = useState<string | null>(null)
-
   return (
-    <Modal title="Retire this seed lot?" onClose={onClose} busy={del.isPending}>
-      <div className="flex flex-col gap-3">
-        <p className="text-sm text-fg">
-          {formatQuantity(lot.quantity)} {lot.unit}
-          {lot.vendor ? ` from ${lot.vendor}` : ''}
-          {lot.packedForYear != null ? `, packed for ${lot.packedForYear}` : ''}.
-        </p>
-        <p className="text-sm text-muted">
-          Anything planted from it stays exactly where it is — it just stops being attributed to this purchase.
-        </p>
-        {error && <Alert>{error}</Alert>}
-        <div className="mt-1 flex justify-end gap-2">
-          <Button type="button" variant="ghost" onClick={onClose} disabled={del.isPending}>
-            Cancel
-          </Button>
-          <Button
-            type="button"
-            variant="danger"
-            disabled={del.isPending}
-            onClick={() =>
-              del.mutate(lot.id, {
-                onSuccess: onClose,
-                onError: (err) => setError(errorMessage(err, 'Could not retire the lot.')),
-              })
-            }
-          >
-            {del.isPending ? 'Retiring…' : 'Retire lot'}
-          </Button>
-        </div>
-      </div>
-    </Modal>
+    <ConfirmModal
+      title="Retire this seed lot?"
+      confirmLabel="Retire lot"
+      busyLabel="Retiring…"
+      errorFallback="Could not retire the lot."
+      onConfirm={() => del.mutateAsync(lot.id)}
+      onClose={onClose}
+    >
+      <p className="text-sm text-fg">
+        {formatQuantity(lot.quantity)} {lot.unit}
+        {lot.vendor ? ` from ${lot.vendor}` : ''}
+        {lot.packedForYear != null ? `, packed for ${lot.packedForYear}` : ''}.
+      </p>
+      <p className="text-sm text-muted">
+        Anything planted from it stays exactly where it is — it just stops being attributed to this purchase.
+      </p>
+    </ConfirmModal>
   )
 }
diff --git a/web/src/components/ui/ConfirmModal.tsx b/web/src/components/ui/ConfirmModal.tsx
new file mode 100644
index 0000000..f346e91
--- /dev/null
+++ b/web/src/components/ui/ConfirmModal.tsx
@@ -0,0 +1,79 @@
+import { useState, type ReactNode } from 'react'
+import { Modal } from '@/components/ui/Modal'
+import { Alert } from '@/components/ui/Alert'
+import { Button } from '@/components/ui/Button'
+import { errorMessage } from '@/lib/api'
+
+/**
+ * A confirm-and-act dialog: a message, then Cancel / Confirm. It owns the shared
+ * shape every confirmation repeated by hand — the busy lock, the inline error on
+ * failure (so a 409 like PLANT_IN_USE is shown, not swallowed), and the footer —
+ * so each caller supplies only its message, its action, and its labels.
+ *
+ * onConfirm runs the action; it resolving closes the dialog, it throwing keeps
+ * the dialog open with the error and re-enables the button for a retry. This is
+ * confirmations only — dialogs with their own inputs (a rename, a form) keep
+ * using Modal directly.
+ */
+export function ConfirmModal({
+  title,
+  children,
+  confirmLabel,
+  busyLabel,
+  confirmVariant = 'danger',
+  confirmDisabled = false,
+  errorFallback,
+  onConfirm,
+  onClose,
+}: {
+  title: string
+  /** The body — what's being confirmed. */
+  children: ReactNode
+  confirmLabel: string
+  /** Label while the action is in flight (e.g. "Deleting…"). */
+  busyLabel: string
+  confirmVariant?: 'danger' | 'primary'
+  /** Extra guard beyond busy (e.g. nothing to clear, no current user). */
+  confirmDisabled?: boolean
+  /** Message if the action throws something without its own user-facing text. */
+  errorFallback: string
+  onConfirm: () => Promise<unknown>
+  onClose: () => void
+}) {
+  const [busy, setBusy] = useState(false)
+  const [error, setError] = useState<string | null>(null)
+
+  async function handleConfirm() {
+    setError(null)
+    setBusy(true)
+    try {
+      await onConfirm()
+      onClose()
+    } catch (err) {
+      setError(errorMessage(err, errorFallback))
+      setBusy(false) // keep the dialog open so the message shows and retry works
+    }
+  }
+
+  return (
+    <Modal title={title} onClose={onClose} busy={busy}>
+      <div className="flex flex-col gap-4">
+        {children}
+        {error && <Alert>{error}</Alert>}
+        <div className="flex justify-end gap-2">
+          <Button type="button" variant="ghost" onClick={onClose} disabled={busy}>
+            Cancel
+          </Button>
+          <Button
+            type="button"
+            variant={confirmVariant}
+            onClick={handleConfirm}
+            disabled={busy || confirmDisabled}
+          >
+            {busy ? busyLabel : confirmLabel}
+          </Button>
+        </div>
+      </div>
+    </Modal>
+  )
+}
diff --git a/web/src/editor/ClearBedModal.tsx b/web/src/editor/ClearBedModal.tsx
index bfc4b7f..ede0ba0 100644
--- a/web/src/editor/ClearBedModal.tsx
+++ b/web/src/editor/ClearBedModal.tsx
@@ -1,5 +1,4 @@
-import { Modal } from '@/components/ui/Modal'
-import { Button } from '@/components/ui/Button'
+import { ConfirmModal } from '@/components/ui/ConfirmModal'
 import { useClearObject } from '@/lib/objects'
 
 /** Confirm clearing every active plop from a focused bed (soft-remove — the rows
@@ -19,27 +18,20 @@ export function ClearBedModal({
 }) {
   const clear = useClearObject(gardenId)
   return (
-    <Modal title="Clear bed" onClose={onClose} busy={clear.isPending}>
-      <div className="flex flex-col gap-4">
-        <p className="text-sm text-muted">
-          Remove all <span className="font-medium text-fg">{plopCount}</span>{' '}
-          {plopCount === 1 ? 'plant' : 'plants'} from{' '}
-          <span className="font-medium text-fg">{objectName}</span>? They're marked removed but kept in history.
-        </p>
-        <div className="flex justify-end gap-2">
-          <Button type="button" variant="ghost" onClick={onClose} disabled={clear.isPending}>
-            Cancel
-          </Button>
-          <Button
-            type="button"
-            variant="danger"
-            disabled={clear.isPending || plopCount === 0}
-            onClick={() => clear.mutate(objectId, { onSuccess: onClose })}
-          >
-            {clear.isPending ? 'Clearing…' : 'Clear bed'}
-          </Button>
-        </div>
-      </div>
-    </Modal>
+    <ConfirmModal
+      title="Clear bed"
+      confirmLabel="Clear bed"
+      busyLabel="Clearing…"
+      confirmDisabled={plopCount === 0}
+      errorFallback="Could not clear the bed."
+      onConfirm={() => clear.mutateAsync(objectId)}
+      onClose={onClose}
+    >
+      <p className="text-sm text-muted">
+        Remove all <span className="font-medium text-fg">{plopCount}</span>{' '}
+        {plopCount === 1 ? 'plant' : 'plants'} from{' '}
+        <span className="font-medium text-fg">{objectName}</span>? They're marked removed but kept in history.
+      </p>
+    </ConfirmModal>
   )
 }
diff --git a/web/src/lib/objects.ts b/web/src/lib/objects.ts
index 9c0a4e0..4694dfc 100644
--- a/web/src/lib/objects.ts
+++ b/web/src/lib/objects.ts
@@ -381,7 +381,9 @@ export function useClearObject(gardenId: number) {
       return res.cleared
     },
     onSettled: () => qc.invalidateQueries({ queryKey: fullKey(gardenId) }),
-    onError: (err) => toast.error(objectErrorMessage(err, 'Could not clear the bed.')),
+    // No toast: the only caller (ClearBedModal → ConfirmModal) shows the failure
+    // inline in the dialog, which is more contextual than a detached toast — and
+    // two of them for one failure is worse than one.
   })
 }