Settings page: themes (Dark, Light, Cyberpunk, Retro) with xterm palettes and hub-synced choice, change password, access tokens, about

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

internal/store/store.go

@@ -19,6 +19,7 @@ type State struct {
 	Terminals []Terminal           `json:"terminals"`
 	Sessions  map[string]time.Time `json:"sessions"`            // token -> expiry
 	Dashboard json.RawMessage      `json:"dashboard,omitempty"` // UI layout prefs, opaque to the server
+	UI        json.RawMessage      `json:"ui,omitempty"`        // theme etc., opaque to the server
 }
 
 type Store struct {