v0.1.0-alpha.94

fix(rail): preview pane auto-syncs to detected dev-server URL

PreviewView only auto-updated from browser_navigate tool calls. When
the agent ran `pnpm dev` and Vite/Next/Astro printed
"Local: http://localhost:5174", the sticky activity bar in the chat
header picked it up but the right-rail preview iframe stayed pointed
at the default localhost:3000. User had to re-type the URL by hand.

Add a parallel useMemo that scans bash + verify tool outputs for the
same "Local: http://" / "ready on http://" banners ChatSurface
already detects (DEV_URL_RE inlined to avoid a circular import).
Effective auto-source is browser_navigate URL > detected dev URL >
default. Iframe reloads on either signal, unless the user has typed
something different in the URL bar.

Bumps to alpha.94.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>