Loki Mode

Added

• Live App Preview panel in the dashboard. While a loki start run is in
  progress the dashboard now embeds the locally-running app (served by the
  existing app-runner) in an iframe so users can interact with it immediately,
  without leaving the dashboard. The panel includes a status badge (running /
  stopped / error), a toolbar with Refresh, Open-in-browser, and Restart
  buttons, and a crash error banner with a redacted technical-details disclosure
  widget.
• loki preview command (alias loki open). Prints the running app URL to
  stdout and opens it in the default browser. Works whether or not the dashboard
  is open.
• GET /api/app-runner/errors endpoint. Returns a redacted error summary for
  the current session. Raw stack traces and absolute paths are stripped before
  the response leaves the server, so only developer-relevant context is
  surfaced.
• Log redaction for GET /api/app-runner/logs. The logs endpoint now applies
  the same redaction filter as the new errors endpoint, closing a pre-existing
  raw-log information-leak.

Notes

• The Live App Preview is entirely local-first: the iframe points at
  localhost, not any hosted service. This closes the "spin up UI to try it"
  gap that cloud builders such as Replit/Lovable/Bolt have, while preserving
  Loki Mode's local-first and no-vendor-lock architecture.