refactor(memory): migration files + embed.FS

- shell/memory/migrations/001_init.sql extraido del schema inline
- sqlite.go: applyMigrations() con embed.FS aplicado al abrir
- aplica regla db_migrations.md (fn_registry/.claude/rules/)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

shell/memory/sqlite.go

@@ -4,38 +4,43 @@ package shellmem
 import (
 	"context"
 	"database/sql"
+	"embed"
 	"fmt"
+	"io/fs"
 	"log/slog"
 	"os"
 	"path/filepath"
+	"sort"
+	"strings"
 	"time"
 
 	"github.com/enmanuel/agents/pkg/llm"
 	"github.com/enmanuel/agents/pkg/memory"
 )
 
-const schema = `
-CREATE TABLE IF NOT EXISTS facts (
-    agent_id   TEXT NOT NULL,
-    subject    TEXT NOT NULL,
-    key        TEXT NOT NULL,
-    value      TEXT NOT NULL,
-    updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
-    PRIMARY KEY (agent_id, subject, key)
-);
+//go:embed migrations/*.sql
+var migrationsFS embed.FS
 
-CREATE TABLE IF NOT EXISTS messages (
-    id         INTEGER PRIMARY KEY AUTOINCREMENT,
-    agent_id   TEXT NOT NULL,
-    room_id    TEXT NOT NULL,
-    role       TEXT NOT NULL,
-    content    TEXT NOT NULL,
-    created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
-);
-
-CREATE INDEX IF NOT EXISTS idx_messages_room ON messages(agent_id, room_id, created_at DESC);
-CREATE INDEX IF NOT EXISTS idx_facts_subject ON facts(agent_id, subject);
-`
+func applyMigrations(db *sql.DB) error {
+	files, err := fs.Glob(migrationsFS, "migrations/*.sql")
+	if err != nil {
+		return err
+	}
+	sort.Strings(files)
+	for _, f := range files {
+		b, err := migrationsFS.ReadFile(f)
+		if err != nil {
+			return err
+		}
+		if _, err := db.Exec(string(b)); err != nil {
+			if strings.Contains(err.Error(), "duplicate column") || strings.Contains(err.Error(), "already exists") {
+				continue
+			}
+			return fmt.Errorf("migrate %s: %w", f, err)
+		}
+	}
+	return nil
+}
 
 // SQLiteStore implements memory.Store using SQLite.
 type SQLiteStore struct {
@@ -54,7 +59,7 @@ func New(dbPath string, logger *slog.Logger) (*SQLiteStore, error) {
 	if err != nil {
 		return nil, fmt.Errorf("open memory db: %w", err)
 	}
-	if _, err := db.Exec(schema); err != nil {
+	if err := applyMigrations(db); err != nil {
 		db.Close()
 		return nil, fmt.Errorf("migrate memory db: %w", err)
 	}