Seed-packet scan UI: camera/upload → proposal → confirm (#102)

The seed-packet capture backend has been live since #94 (POST /seed-lots/scan
and /seed-lots/from-packet, with /capabilities reporting `vision`), but there was
no UI, so the feature Steve asked for — "take a picture of a packet and it
auto-creates" — was unreachable. This adds the mobile-first UI.

- Entry point in the Plants catalog ("Scan a packet"), shown only where
  `capabilities.vision` is on — so it's never a dead button on an instance with
  no vision model. Adds `vision` to the capabilities schema (both flags now
  default false, so a partial response hides a feature rather than failing parse).
- ScanPacketModal: two phases in one dialog. Capture uses a file input with
  `accept="image/*" capture="environment"` so a phone opens the camera directly
  (also picks an existing photo; HEIC is handled server-side). Review shows the
  extracted fields read-only for context, then an editable confirm — pick a ranked
  existing candidate (with its match reason) or create a new variety prefilled from
  the packet. Nothing commits blind, which is the whole point of the backend's
  never-auto-create design.
- New data layer (lib/seedPacket.ts): zod schemas mirroring the backend
  (SeedPacket / PacketProposal / PacketResult), the scan + confirm mutations, and
  the pure prefill helpers (newPlantDefaults / lotDefaults) — unit-tested, since
  the prefill mapping (unknown category, missing spacing, seed-count→unit) is
  where the bugs hide.
- api.ts learns to send FormData as multipart (no JSON content-type) for the
  scan upload, via a new api.postForm.

Frontend only; no backend or route change. Last open child of epic #96.

Live camera→vision→proposal verification needs a vision-configured instance
(the flow is model-gated and unreachable locally, same as the assistant);
the confirm half and all prefill logic are covered by tests.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01H3zbym8Doka2d7D48maSgZ

web/src/lib/seedPacket.test.ts

@@ -0,0 +1,120 @@
+import { describe, expect, it } from 'vitest'
+import {
+  lotDefaults,
+  newPlantDefaults,
+  packetProposalSchema,
+  seedPacketSchema,
+  PACKET_PLANT_COLOR,
+  PACKET_PLANT_ICON,
+} from './seedPacket'
+
+// A full proposal as the backend sends it, for the schema + prefill tests.
+const proposal = {
+  packet: {
+    species: 'garlic',
+    variety: 'Music',
+    category: 'vegetable',
+    vendor: "Johnny's",
+    sku: 'G-123',
+    lotCode: 'L9',
+    packedForYear: 2026,
+    daysToMaturity: 90,
+    spacingCm: 15,
+    seedCount: 12,
+  },
+  candidates: [
+    {
+      plant: {
+        id: 7,
+        name: 'Music',
+        category: 'vegetable',
+        spacingCm: 15,
+        color: '#fff',
+        icon: '🧄',
+        notes: '',
+        version: 1,
+        createdAt: '2026-01-01T00:00:00Z',
+        updatedAt: '2026-01-01T00:00:00Z',
+      },
+      reason: 'exact name',
+    },
+  ],
+  suggestedName: 'Music',
+  suggestedCategory: 'vegetable',
+}
+
+describe('seedPacketSchema', () => {
+  it('fills defaults for a sparse packet (only what was printed)', () => {
+    // A packet where the model only read a species — everything else absent.
+    const p = seedPacketSchema.parse({ species: 'basil' })
+    expect(p.species).toBe('basil')
+    expect(p.variety).toBe('')
+    expect(p.spacingCm).toBeNull()
+    expect(p.seedCount).toBeNull()
+    expect(p.packedForYear).toBeNull()
+  })
+})
+
+describe('packetProposalSchema', () => {
+  it('parses a full proposal including candidates', () => {
+    const p = packetProposalSchema.parse(proposal)
+    expect(p.candidates).toHaveLength(1)
+    expect(p.candidates[0].plant.id).toBe(7)
+    expect(p.candidates[0].reason).toBe('exact name')
+    expect(p.suggestedName).toBe('Music')
+  })
+
+  it('defaults candidates to empty when absent', () => {
+    const p = packetProposalSchema.parse({ packet: { species: 'kale' } })
+    expect(p.candidates).toEqual([])
+    expect(p.suggestedName).toBe('')
+  })
+})
+
+describe('newPlantDefaults', () => {
+  it('prefills name/category/spacing/days/vendor from the proposal', () => {
+    const np = newPlantDefaults(packetProposalSchema.parse(proposal))
+    expect(np.name).toBe('Music')
+    expect(np.category).toBe('vegetable')
+    expect(np.spacingCm).toBe(15)
+    expect(np.daysToMaturity).toBe(90)
+    expect(np.vendor).toBe("Johnny's")
+    // No icon/color on a packet — placeholders the user can change later.
+    expect(np.icon).toBe(PACKET_PLANT_ICON)
+    expect(np.color).toBe(PACKET_PLANT_COLOR)
+  })
+
+  it('falls back to a safe category and default spacing when the packet lacks them', () => {
+    const np = newPlantDefaults(
+      packetProposalSchema.parse({
+        packet: { species: 'mystery' },
+        suggestedName: 'mystery',
+        suggestedCategory: 'not-a-real-category',
+      }),
+    )
+    // An unknown category must not leak through — CreatePlant would reject it.
+    expect(np.category).toBe('vegetable')
+    // No printed spacing → the same default the manual form uses.
+    expect(np.spacingCm).toBe(30)
+    expect(np.daysToMaturity).toBeNull()
+  })
+})
+
+describe('lotDefaults', () => {
+  it('reads a seed count as "<n> seeds"', () => {
+    const lot = lotDefaults(seedPacketSchema.parse(proposal.packet))
+    expect(lot.quantity).toBe(12)
+    expect(lot.unit).toBe('seeds')
+    expect(lot.vendor).toBe("Johnny's")
+    expect(lot.sku).toBe('G-123')
+    expect(lot.lotCode).toBe('L9')
+    expect(lot.packedForYear).toBe(2026)
+  })
+
+  it('defaults to one packet when no seed count is printed', () => {
+    const lot = lotDefaults(seedPacketSchema.parse({ species: 'basil' }))
+    expect(lot.quantity).toBe(1)
+    expect(lot.unit).toBe('packets')
+    expect(lot.packedForYear).toBeNull()
+  })
+})