feat: executions, assertions y bucle reactivo en fn_operations

Añade Execution, Assertion, AssertionResult al paquete fn_operations.
Motor de evaluación de assertions con reescritura SQL automática.
Bucle reactivo: ExecuteAndReact evalúa assertions y cambia status de
entities (corrupted/stale) + auto-crea proposals en registry.
CLI fn ops: assertion (add/list/show/delete/eval) y execution (add/list/show).
Migración 002_executions_assertions.sql con FTS para assertions.

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

fn_operations/migrate.go

@@ -0,0 +1,117 @@
+package fn_operations
+
+import (
+	"database/sql"
+	"embed"
+	"fmt"
+	"path"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+)
+
+//go:embed migrations/*.sql
+var migrationsFS embed.FS
+
+const migrationTableSQL = `
+CREATE TABLE IF NOT EXISTS schema_migrations (
+	version    INTEGER PRIMARY KEY,
+	name       TEXT NOT NULL,
+	applied_at TEXT NOT NULL
+);`
+
+// migrate applies pending migrations to the database.
+func migrate(conn *sql.DB) error {
+	if _, err := conn.Exec(migrationTableSQL); err != nil {
+		return fmt.Errorf("creating schema_migrations table: %w", err)
+	}
+
+	current, err := currentVersion(conn)
+	if err != nil {
+		return err
+	}
+
+	files, err := listMigrations()
+	if err != nil {
+		return err
+	}
+
+	for _, mf := range files {
+		if mf.version <= current {
+			continue
+		}
+
+		content, err := migrationsFS.ReadFile(path.Join("migrations", mf.filename))
+		if err != nil {
+			return fmt.Errorf("reading migration %s: %w", mf.filename, err)
+		}
+
+		tx, err := conn.Begin()
+		if err != nil {
+			return fmt.Errorf("beginning transaction for migration %d: %w", mf.version, err)
+		}
+
+		if _, err := tx.Exec(string(content)); err != nil {
+			tx.Rollback()
+			return fmt.Errorf("applying migration %s: %w", mf.filename, err)
+		}
+
+		if _, err := tx.Exec(
+			"INSERT INTO schema_migrations (version, name, applied_at) VALUES (?, ?, ?)",
+			mf.version, mf.filename, time.Now().UTC().Format(time.RFC3339),
+		); err != nil {
+			tx.Rollback()
+			return fmt.Errorf("recording migration %s: %w", mf.filename, err)
+		}
+
+		if err := tx.Commit(); err != nil {
+			return fmt.Errorf("committing migration %s: %w", mf.filename, err)
+		}
+	}
+
+	return nil
+}
+
+func currentVersion(conn *sql.DB) (int, error) {
+	var v int
+	err := conn.QueryRow("SELECT COALESCE(MAX(version), 0) FROM schema_migrations").Scan(&v)
+	if err != nil {
+		return 0, fmt.Errorf("reading current schema version: %w", err)
+	}
+	return v, nil
+}
+
+type migrationFile struct {
+	version  int
+	filename string
+}
+
+func listMigrations() ([]migrationFile, error) {
+	entries, err := migrationsFS.ReadDir("migrations")
+	if err != nil {
+		return nil, fmt.Errorf("reading migrations directory: %w", err)
+	}
+
+	var files []migrationFile
+	for _, e := range entries {
+		if e.IsDir() || !strings.HasSuffix(e.Name(), ".sql") {
+			continue
+		}
+		parts := strings.SplitN(e.Name(), "_", 2)
+		if len(parts) < 2 {
+			continue
+		}
+		v, err := strconv.Atoi(parts[0])
+		if err != nil {
+			continue
+		}
+		files = append(files, migrationFile{version: v, filename: e.Name()})
+	}
+
+	sort.Slice(files, func(i, j int) bool {
+		return files[i].version < files[j].version
+	})
+
+	return files, nil
+}