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

internal/handlers/context.go

@@ -0,0 +1,15 @@
+package handlers
+
+import (
+	"database/sql"
+	"log/slog"
+
+	"git.soup.land/soup/sxgo/ssr"
+)
+
+// RequestContext holds dependencies that are injected into every request handler.
+type RequestContext struct {
+	DB        *sql.DB
+	Logger    *slog.Logger
+	TmplCache *ssr.TmplCache
+}