Fix Chrome extension send after the MV3 service worker drops

[Obooman]

The packed Chrome extension release, installed in branded Chrome 148 via Developer mode → Load unpacked (Chrome 137+ ignores --load-extension), auto-discovers vavd and shows the desktop session shell. Two release-install gaps showed up:

1. Send died after the MV3 worker recycled. The side panel kept a stale Connected chip; window.vav.agent.send threw Attempting to use a disconnected port object and vavd never got the turn.
2. Brand marks 404ed. esbuild emits ./deepseek-*.svg. sidepanel.html lives at the extension root, so Chrome requested chrome-extension://<id>/deepseek-*.svg and showed an Errors chip.

Fixes

• Rebind the sidepanel port, queue outbound frames, flush on reconnect, mark status reconnecting
• <base href="phone/"> so bundled assets resolve next to phone.js
• publicPath: './' in the phone-ui build
• Unit tests for port reconnect; pack test for the document base

Installed-Chrome verification (headed Chrome 148 + unpacked release zip)

Check	Result
A. Desktop shell + Connected · Release Ext Test	Pass
B. New session, horizontal composer, desktop run bar	Pass
C. hello from the release extension → You + e2e stub reply	Pass (after reconnect fix)
D. Tab chip “Install guide”, Include on, chip above composer	Pass
E. chrome://extensions — VAV 1.19.0, background.js service worker active	Pass

The Cursor computerUse subagent could not start (Claude usage exceeded). The same pass was driven on DISPLAY=:1 against the already-installed release tree at /tmp/vav-ext-release.