feat(phase-b): Supabase navigation store, snapshot service, auth wiring

navigationStore: rewritten off Neo4j db names — Supabase whiteboard_rooms table,
  setAuthInfo(token, userId) pattern, auto-creates default room per context on first use
snapshotService: rewritten to Supabase Storage REST (/storage/v1/object/authenticated/cc.users/…),
  setAccessToken() instance method, static methods take accessToken not dbName
AuthContext/NeoUserContext: auth injected into nav store, no Neo4j db names required
singlePlayerPage: loadNodeData no longer calls Neo4j; snapshot wired via accessToken
navigation types: NeoGraphNode updated for Supabase-backed tree structure
transcriptionStore/Service: getSession() removed, accessToken via AuthContext
LLMConfigModal: auth context wiring fixes
GraphNavigator/GraphSidebar: updated nav components

Co-Authored-By: Claude Sonnet 4.6 <[email protected]>

src/types/navigation.ts

@@ -227,6 +227,13 @@ export interface UnifiedContextSwitch {
 }
 
 // Navigation Actions Interface
+export interface NeoGraphNode {
+    neo4j_node_id: string;
+    neo4j_db_name: string;
+    node_type: string;
+    label: string;
+}
+
 export interface NavigationActions {
     // Unified Context Switch
     switchContext: (contextSwitch: UnifiedContextSwitch, userDbName: string | null, workerDbName: string | null) => Promise<void>;
@@ -239,6 +246,7 @@ export interface NavigationActions {
     // Node Navigation
     navigate: (nodeId: string, dbName: string) => Promise<void>;
     navigateToNode: (node: NavigationNode, userDbName: string | null, workerDbName: string | null) => Promise<void>;
+    navigateToNeoNode: (neoNode: NeoGraphNode) => Promise<void>;
     
     // History Navigation
     goBack: () => void;