feat(v0.6): show CLAUDE.md on the project detail page + /init generate/update button

The detail page now reads <repo>/CLAUDE.md and shows it in a scrollable
monospace box, with one smart button: "↻ Update" when it exists / "✨ Generate"
when it doesn't. The button opens an interactive Claude session in the repo
running /init (claude "/init") so you review what it writes — reuses the project
launcher, no new backend orchestration, stays a byte-shuttle.

- ProjectDetail += hasClaudeMd / claudeMd; buildProjectDetail reads CLAUDE.md
  (truncated 64KB, best-effort, in the existing Promise.all)
- renderProjectDetail: CLAUDE.md section (content box or empty state) + button
- style.css: .proj-section-row / .proj-claudemd-btn / .proj-claudemd

Tests +5 (458): backend read present/absent; frontend content+Update,
empty+Generate, button opens `claude "/init"`. Verified: tsc clean, full suite
green, build OK, curl returns the content, in-browser shows the box + button.

test/projects-panel.test.ts

@@ -484,4 +484,28 @@ describe('renderProjectDetail', () => {
     const root = renderProjectDetail(detail({ isGit: false, branch: undefined }), hooks(), cbs())
     expect(root.textContent).toContain('Not a git repository')
   })
+
+  it('shows CLAUDE.md content + an Update button when present', () => {
+    const root = renderProjectDetail(detail({ hasClaudeMd: true, claudeMd: '# Rules\nbe nice' }), hooks(), cbs())
+    expect(root.querySelector('.proj-claudemd')?.textContent).toContain('be nice')
+    expect(root.querySelector('.proj-claudemd-btn')?.textContent).toContain('Update')
+  })
+
+  it('shows a Generate button + empty state when CLAUDE.md is absent', () => {
+    const root = renderProjectDetail(detail({ hasClaudeMd: false }), hooks(), cbs())
+    expect(root.querySelector('.proj-claudemd')).toBeNull()
+    expect(root.textContent).toContain('No CLAUDE.md yet')
+    expect(root.querySelector('.proj-claudemd-btn')?.textContent).toContain('Generate')
+  })
+
+  it('the CLAUDE.md button opens a Claude /init session in the repo', () => {
+    const h = hooks()
+    const root = renderProjectDetail(
+      detail({ name: 'r', path: '/p/r', hasClaudeMd: true, claudeMd: 'x' }),
+      h,
+      cbs(),
+    )
+    ;(root.querySelector('.proj-claudemd-btn') as HTMLButtonElement).click()
+    expect(h.onOpenProject).toHaveBeenCalledWith('/p/r', 'r', 'claude "/init"\r')
+  })
 })