fix: comprehensive QA audit — light mode, accessibility, error handling, code quality

- Fix light mode: theme-aware graph node labels, remove prose-invert for
  theme-safe markdown, add brand/semantic color overrides for light backgrounds
- Add 404 catch-all route redirecting unknown paths to /chat
- FalkorDB: add .catch() to connectPromise, add ensureConnected() to all
  store methods (createLiteral, relateNode, relateLiteral, deleteCollection)
- Accessibility: dialog role/aria-modal, toast aria-live, dismiss/zoom/search
  button aria-labels, close panel aria-label
- Lazy-load ForceGraph2D (splits 189KB into separate chunk, main bundle -26%)
- Cap conversation localStorage at 200 messages to prevent quota overflow
- Fix pnpm test: add --passWithNoTests to cli/mcp packages
- Add upload error notification instead of silent catch
- Remove unused class-variance-authority dep and dead tabs.tsx component
- Add @types/node to flow package devDependencies
- Remove stale FIXME comment in messages.ts

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ts/packages/client/src/models/messages.ts

@@ -1,6 +1,5 @@
 import { Triple, Term } from "./Triple.js";
 
-// FIXME: Better types?
 export type Request = object;
 export type Response = object;
 export type Error = object | string;