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/jackc/pgx/v5/internal/stmtcache/stmtcache.go

@@ -0,0 +1,45 @@
+// Package stmtcache is a cache for statement descriptions.
+package stmtcache
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+
+	"github.com/jackc/pgx/v5/pgconn"
+)
+
+// StatementName returns a statement name that will be stable for sql across multiple connections and program
+// executions.
+func StatementName(sql string) string {
+	digest := sha256.Sum256([]byte(sql))
+	return "stmtcache_" + hex.EncodeToString(digest[0:24])
+}
+
+// Cache caches statement descriptions.
+type Cache interface {
+	// Get returns the statement description for sql. Returns nil if not found.
+	Get(sql string) *pgconn.StatementDescription
+
+	// Put stores sd in the cache. Put panics if sd.SQL is "". Put does nothing if sd.SQL already exists in the cache.
+	Put(sd *pgconn.StatementDescription)
+
+	// Invalidate invalidates statement description identified by sql. Does nothing if not found.
+	Invalidate(sql string)
+
+	// InvalidateAll invalidates all statement descriptions.
+	InvalidateAll()
+
+	// GetInvalidated returns a slice of all statement descriptions invalidated since the last call to RemoveInvalidated.
+	GetInvalidated() []*pgconn.StatementDescription
+
+	// RemoveInvalidated removes all invalidated statement descriptions. No other calls to Cache must be made between a
+	// call to GetInvalidated and RemoveInvalidated or RemoveInvalidated may remove statement descriptions that were
+	// never seen by the call to GetInvalidated.
+	RemoveInvalidated()
+
+	// Len returns the number of cached prepared statement descriptions.
+	Len() int
+
+	// Cap returns the maximum number of cached prepared statement descriptions.
+	Cap() int
+}