Initial lookbook implementation

Pinterest-style visual bookmarking app with:
- URL metadata extraction (OG/Twitter meta, oEmbed fallback)
- Image caching in Postgres with 480px thumbnails
- Multi-tag filtering with Ctrl/Cmd for OR mode
- Fuzzy tag suggestions and inline tag editing
- Browser console auth() with first-use password setup
- Brutalist UI with Commit Mono font and Pico CSS
- Light/dark mode via browser preference

vendor/github.com/pressly/goose/v3/lock/locker.go

@@ -0,0 +1,32 @@
+// Package lock defines the Locker interface and implements the locking logic.
+package lock
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+)
+
+var (
+	// ErrLockNotImplemented is returned when the database does not support locking.
+	ErrLockNotImplemented = errors.New("lock not implemented")
+	// ErrUnlockNotImplemented is returned when the database does not support unlocking.
+	ErrUnlockNotImplemented = errors.New("unlock not implemented")
+)
+
+// SessionLocker is the interface to lock and unlock the database for the duration of a session. The
+// session is defined as the duration of a single connection and both methods must be called on the
+// same connection.
+type SessionLocker interface {
+	SessionLock(ctx context.Context, conn *sql.Conn) error
+	SessionUnlock(ctx context.Context, conn *sql.Conn) error
+}
+
+// Locker is the interface to lock and unlock the database.
+//
+// Unlike [SessionLocker], the Lock and Unlock methods are called on a [*sql.DB] and do not require
+// the same connection to be used for both methods.
+type Locker interface {
+	Lock(ctx context.Context, db *sql.DB) error
+	Unlock(ctx context.Context, db *sql.DB) error
+}