docs: examples for every hard requirement + mort migration blueprint

Phase 7: nine runnable examples/ programs (parse, failover chains with
trailing alias, tiers, LLM_* env providers, multimodal, tool loop,
Generate[T], agent, skills); docs/mort-migration.md mapping mort's
go-llm/go-agentkit usage onto majordomo APIs with the planned additive
library extensions and conversion order; README finalized with the
complete matrix.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

examples/tiers/main.go

@@ -0,0 +1,36 @@
+// Command tiers demonstrates custom tiers: register an alias once, then
+// address models by task shape ("thinking", "workhorse") instead of
+// hard-coding model strings at every call site.
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"log"
+
+	"gitea.stevedudenhoeffer.com/steve/majordomo"
+)
+
+func main() {
+	flag.Parse()
+
+	reg := majordomo.New()
+	reg.RegisterAlias("thinking", "ollama-cloud/minimax-m3:cloud,ollama-cloud/kimi-k2.6:cloud")
+	reg.RegisterAlias("workhorse", "ollama-cloud/minimax-m2.7:cloud,ollama-cloud/qwen3-coder:480b-cloud")
+	// Tiers can reference other tiers; expansion is recursive (with cycle
+	// detection), so "best-effort" is thinking with a workhorse tail.
+	reg.RegisterAlias("best-effort", "thinking,workhorse")
+
+	m, err := reg.Parse("best-effort")
+	if err != nil {
+		log.Fatalf("parse: %v", err)
+	}
+	resp, err := m.Generate(context.Background(), majordomo.Request{
+		Messages: []majordomo.Message{majordomo.UserText("One sentence: what is a model tier?")},
+	})
+	if err != nil {
+		log.Fatalf("generate: %v", err)
+	}
+	fmt.Printf("[%s] %s\n", resp.Model, resp.Text())
+}