fix(web-ui): cwd-relative path summaries, sweep glare rework, uniform 16px chat rhythm

Tool row summaries strip the session workspace root; the running sweep
becomes a glare-band overlay (deepsuite ShimmerText pattern); assistant
nodes that render nothing no longer split tool-row groups; block and
tool-row spacing collapse to one 16px rhythm.

packages/client/ui-conversation/tests/chat-tool-row.spec.tsx

@@ -64,6 +64,16 @@ describe('tool-call-model', () => {
     expect(toolRowModel('', running({ argsRaw: '' })).summary).toBe('c1')
   })
 
+  it('displays workspace-rooted paths relative to the session cwd', () => {
+    const cwd = '/Users/u/ws/'
+    expect(toolRowModel('edit', running({ name: 'edit', argsRaw: '{"file_path":"/Users/u/ws/src/x.ts"}' }), cwd).summary).toBe('src/x.ts')
+    expect(toolRowModel('read', running({ name: 'read', argsRaw: '{"path":"/Users/u/ws/a.md"}' }), cwd).summary).toBe('a.md')
+    // Paths outside the workspace (and non-path summaries) stay verbatim.
+    expect(toolRowModel('read', running({ name: 'read', argsRaw: '{"path":"/etc/hosts"}' }), cwd).summary).toBe('/etc/hosts')
+    expect(toolRowModel('bash', running({ argsRaw: '{"command":"pwd"}' }), cwd).summary).toBe('pwd')
+    expect(toolRowModel('read', running({ name: 'read', argsRaw: '{"path":"/Users/u/ws/a.md"}' }), '').summary).toBe('/Users/u/ws/a.md')
+  })
+
   it('body pretty-prints JSON args, keeps raw non-JSON, null when empty', () => {
     expect(toolRowModel('bash', running({ argsRaw: '{"a":1}' })).body).toBe('{\n  "a": 1\n}')
     expect(toolRowModel('bash', running({ argsRaw: 'raw' })).body).toBe('raw')