feat: proposals en registry

Añade sistema de proposals al registry: modelos (ProposalKind, ProposalStatus),
CRUD completo (Insert/Get/Update/Delete/List/Search con FTS), validación,
migración 002_proposals.sql y subcomando CLI fn proposal (add/list/show/update).
Motor de migraciones con embed.FS reemplaza schema estático.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

registry/store_test.go

@@ -151,6 +151,138 @@ func TestPurge(t *testing.T) {
 	}
 }
 
+func TestProposalCRUD(t *testing.T) {
+	db := tempDB(t)
+
+	p := &Proposal{
+		ID:          "proposal_test_1",
+		Kind:        ProposalNewFunction,
+		Title:       "Add retry with backoff",
+		Description: "Exponential backoff for HTTP clients",
+		Evidence:    map[string]any{"assertion_ids": []any{"a1", "a2"}},
+		CreatedBy:   "agent",
+	}
+
+	if err := db.InsertProposal(p); err != nil {
+		t.Fatalf("insert: %v", err)
+	}
+
+	if p.Status != ProposalPending {
+		t.Errorf("default status = %q, want pending", p.Status)
+	}
+
+	got, err := db.GetProposal("proposal_test_1")
+	if err != nil {
+		t.Fatalf("get: %v", err)
+	}
+	if got.Title != "Add retry with backoff" {
+		t.Errorf("title = %q, want %q", got.Title, "Add retry with backoff")
+	}
+	if got.Evidence["assertion_ids"] == nil {
+		t.Error("evidence should contain assertion_ids")
+	}
+
+	// Update
+	got.Status = ProposalApproved
+	got.ReviewedBy = "lucas"
+	if err := db.UpdateProposal(got); err != nil {
+		t.Fatalf("update: %v", err)
+	}
+	updated, _ := db.GetProposal("proposal_test_1")
+	if updated.Status != ProposalApproved {
+		t.Errorf("status = %q, want approved", updated.Status)
+	}
+	if updated.ReviewedBy != "lucas" {
+		t.Errorf("reviewed_by = %q, want lucas", updated.ReviewedBy)
+	}
+
+	// List with filter
+	db.InsertProposal(&Proposal{
+		ID: "proposal_test_2", Kind: ProposalImproveType, TargetID: "ohlcv_go_finance",
+		Title: "Improve OHLCV", CreatedBy: "agent",
+	})
+
+	all, err := db.ListProposals("", "")
+	if err != nil {
+		t.Fatalf("list all: %v", err)
+	}
+	if len(all) != 2 {
+		t.Errorf("list all = %d, want 2", len(all))
+	}
+
+	byKind, _ := db.ListProposals(ProposalNewFunction, "")
+	if len(byKind) != 1 {
+		t.Errorf("list by kind = %d, want 1", len(byKind))
+	}
+
+	byStatus, _ := db.ListProposals("", ProposalPending)
+	if len(byStatus) != 1 {
+		t.Errorf("list by status pending = %d, want 1", len(byStatus))
+	}
+
+	// Search FTS
+	found, err := db.SearchProposals("backoff", "", "")
+	if err != nil {
+		t.Fatalf("search: %v", err)
+	}
+	if len(found) != 1 {
+		t.Errorf("search 'backoff' = %d, want 1", len(found))
+	}
+
+	// Delete
+	if err := db.DeleteProposal("proposal_test_1"); err != nil {
+		t.Fatalf("delete: %v", err)
+	}
+	_, err = db.GetProposal("proposal_test_1")
+	if err == nil {
+		t.Error("expected error after delete")
+	}
+}
+
+func TestValidateProposal(t *testing.T) {
+	tests := []struct {
+		name    string
+		p       Proposal
+		wantErr bool
+	}{
+		{"valid new_function", Proposal{ID: "p1", Kind: ProposalNewFunction, Title: "test"}, false},
+		{"valid improve with target", Proposal{ID: "p2", Kind: ProposalImproveFunction, Title: "test", TargetID: "fn_go_core"}, false},
+		{"missing title", Proposal{ID: "p3", Kind: ProposalNewFunction}, true},
+		{"missing kind", Proposal{ID: "p4", Title: "test"}, true},
+		{"improve without target", Proposal{ID: "p5", Kind: ProposalImproveType, Title: "test"}, true},
+		{"invalid kind", Proposal{ID: "p6", Kind: "invalid", Title: "test"}, true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := ValidateProposal(&tt.p)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("ValidateProposal() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestMigrations(t *testing.T) {
+	db := tempDB(t)
+
+	// Verify schema_migrations table exists and has entries
+	var count int
+	err := db.conn.QueryRow("SELECT COUNT(*) FROM schema_migrations").Scan(&count)
+	if err != nil {
+		t.Fatalf("query schema_migrations: %v", err)
+	}
+	if count < 2 {
+		t.Errorf("expected at least 2 migrations, got %d", count)
+	}
+
+	// Verify proposals table exists
+	_, err = db.conn.Exec("SELECT 1 FROM proposals LIMIT 1")
+	if err != nil {
+		t.Fatalf("proposals table should exist: %v", err)
+	}
+}
+
 func TestDrop(t *testing.T) {
 	path := filepath.Join(t.TempDir(), "drop.db")
 	db, err := Open(path)