feat(sidebar): spin a gray indicator on clean workspaces with a working agent

[Ziinc]

A clean workspace with a running agent had no sidebar indicator, so it looked idle.

Change

getWorkspaceStatusIndicator now returns a neutral spinner for a clean workspace whose agent is streaming output:

• { color: "neutral", spin: true, label: "Agent working" }, drawn gray (text-muted-foreground);
• the test id is the same workspace-status-indicator-<id>.
  Behaviour otherwise:
• Changed and conflicted workspaces keep their yellow and red indicators, which spin while an agent streams, as before.
• The spinner follows the terminal's existing streaming state. It stops about 2 s after the agent's last output, which is when the terminal reports idle. An agent that is open but idle in a clean workspace shows nothing, the same as an idle agent in a changed workspace shows a static dot.
• The home repo row has no status indicator at all, and I left it that way. It's a separate change if you want one there.

Tests

• New unit test src/lib/workspace-status-indicator.test.ts.
• New integration test test/integration/sidebar-agent-spinner.test.tsx, using the fake agent: a clean workspace shows no indicator; after Cmd+] it shows the "Agent working" spinner; the spinner goes away once the agent is idle. Without the change this test fails.
• The workspace-agent-session-spinner screenshot spec has a new capture, 04-clean-working. I checked it: feat/session-clean shows the gray spinner, and feat/no-session-clean shows nothing.
• tsc and lint are clean. Unit tests pass (800/800), and test/integration/workspace/** passes (136/136).
  Generated by Claude Code

[Ziinc]

test-js / test:integration failed in one test: workspace/code.test.tsx › clicking a non-readme file opens FileBrowser and allows line comments to start an agent. It timed out after 10 s waiting for [data-testid="code-line"] to render in the file browser.

I don't think this PR caused it:

• This PR only changes the sidebar status indicator (workspace-status-indicator.ts). It doesn't touch the file browser.
• The same test passed on fix(terminal): keep focus on close, relaunch without the task on model change, drop Reset #628 and refactor: remove Mission Control and dead terminal code; key agent columns "agent-<id>" #629 against the same base.
• It passes three times out of three locally on this branch's head (676a66e2).

I haven't found or made a fix for it. I'm re-running the failed job once. If it fails again I'll treat it as a real failure and dig in.

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Generated by Claude Code