Merge #720: fix(log-viewer): stop reconnecting after a startup error

The floating log viewer reconnected every few seconds when its tail-file
stream ended with a startup error (path refused, file missing, too large,
stream limit, tail spawn failure). It now closes the EventSource on an
`error` message that arrives before `connected`; an established stream
keeps its reconnect.

Squashed from #720 (johoja12). Maintainer edits while landing, as the
review said: the onerror close is dropped (it stopped the browser's own
retry after a transport failure, leaving the window on "Connecting"),
the test's check for a button nothing renders is gone, and the stubbed
stream sets `retry: 200` so a reconnect, if one came, shows within the
shorter wait.

Co-authored-by: Codeman maintainer <kay@stutz.science>
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

config/test-suites.ts

@@ -63,6 +63,7 @@ export const BROWSER_TEST_GLOBS = [
   'test/desktop-connect-page.browser.test.ts', // no server: the page is served by request interception
   'test/local-model-ui.browser.test.ts',
   'test/home-breakpoint-swap.browser.test.ts',
+  'test/log-viewer-reconnect.browser.test.ts',
 ];
 
 /**