add Claude meta sidebar — activity + team roster

An always-pickable left-panel tab. Shows Claude activity read from
~/.claude/stats-cache.json (latest day's messages/sessions/tool-calls +
lifetime totals, polled) and, when a tmux agent team is running, a roster
of its members (colour · name · agent type · model) from the observer's
join/left events — nothing re-tailed here.

Scoped down from the original ticket: the account/team token budget isn't
programmatically exposed under subscription auth (TUI-only; upstream
#44328) and live per-member status needs the teammate status stream wired
onto the bus — filed as T-158 and T-157 respectively.

T-141.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

lib/builtin/claude/src/claude_meta_sidebar.dart

@@ -0,0 +1,174 @@
+/// Claude meta sidebar (T-141): an always-pickable left-panel tab showing
+/// Claude *activity* (from `~/.claude/stats-cache.json`, polled) and, when a
+/// tmux agent team is running, a roster of its members (from the
+/// TeamObserver's join/left events — not re-tailed here).
+///
+/// The account/team token budget is intentionally absent: it isn't
+/// programmatically exposed under subscription auth (see project memory /
+/// GitHub anthropics/claude-code#44328). Live per-member status (mode /
+/// context) is a follow-up that needs the teammate status stream on the bus.
+library;
+
+import 'dart:async';
+import 'dart:io';
+
+import 'package:clide/builtin/claude/src/claude_stats.dart';
+import 'package:clide/builtin/claude/src/claude_status.dart' show shortModelLabel;
+import 'package:clide/builtin/claude/src/team_panel_host.dart' show teamColor;
+import 'package:clide/kernel/kernel.dart';
+import 'package:clide/widgets/widgets.dart';
+import 'package:flutter/widgets.dart';
+
+class ClaudeMetaSidebar extends StatefulWidget {
+  const ClaudeMetaSidebar({super.key, this.statsLoader, this.pollInterval = const Duration(seconds: 20)});
+
+  /// Loads the activity stats; defaults to reading `~/.claude/stats-cache.json`.
+  /// Injected in tests so they don't touch the real filesystem.
+  final Future<ClaudeStats> Function()? statsLoader;
+
+  /// How often to reload the stats. `Duration.zero` disables polling
+  /// (initial load only) — used by tests to avoid a pending timer.
+  final Duration pollInterval;
+
+  @override
+  State<ClaudeMetaSidebar> createState() => _ClaudeMetaSidebarState();
+}
+
+class _ClaudeMetaSidebarState extends State<ClaudeMetaSidebar> {
+  ClaudeStats _stats = const ClaudeStats();
+  final List<TeamMemberJoined> _members = [];
+  StreamSubscription<TeamMemberJoined>? _joinSub;
+  StreamSubscription<TeamMemberLeft>? _leftSub;
+  Timer? _timer;
+  late final Future<ClaudeStats> Function() _load;
+  bool _subscribed = false;
+
+  @override
+  void initState() {
+    super.initState();
+    _load = widget.statsLoader ?? _fileLoader();
+    unawaited(_refreshStats());
+    if (widget.pollInterval > Duration.zero) {
+      _timer = Timer.periodic(widget.pollInterval, (_) => unawaited(_refreshStats()));
+    }
+  }
+
+  static Future<ClaudeStats> Function() _fileLoader() {
+    final home = Platform.environment['HOME'];
+    final file = home == null ? null : File('$home/.claude/stats-cache.json');
+    return () async {
+      if (file == null || !await file.exists()) return const ClaudeStats();
+      try {
+        return parseClaudeStats(await file.readAsString());
+      } catch (_) {
+        return const ClaudeStats();
+      }
+    };
+  }
+
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+    if (_subscribed) return;
+    _subscribed = true;
+    final events = ClideKernel.of(context).events;
+    _joinSub = events.on<TeamMemberJoined>().listen((m) {
+      if (_members.any((x) => x.agentId == m.agentId)) return;
+      setState(() => _members.add(m));
+    });
+    _leftSub = events.on<TeamMemberLeft>().listen((m) {
+      setState(() => _members.removeWhere((x) => x.agentId == m.agentId));
+    });
+  }
+
+  Future<void> _refreshStats() async {
+    final stats = await _load();
+    if (mounted) setState(() => _stats = stats);
+  }
+
+  @override
+  void dispose() {
+    _timer?.cancel();
+    _joinSub?.cancel();
+    _leftSub?.cancel();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final tokens = ClideTheme.of(context).surface;
+    return ListView(
+      padding: const EdgeInsets.all(12),
+      children: [
+        _sectionHeader(tokens, 'Activity'),
+        _activity(tokens),
+        const SizedBox(height: 16),
+        _sectionHeader(tokens, 'Team${_members.isEmpty ? '' : '  ·  ${_members.length}'}'),
+        _roster(tokens),
+      ],
+    );
+  }
+
+  Widget _sectionHeader(SurfaceTokens tokens, String label) => Padding(
+        padding: const EdgeInsets.only(bottom: 6),
+        child: ClideText(label, fontSize: clideFontSmall, color: tokens.globalTextMuted),
+      );
+
+  Widget _activity(SurfaceTokens tokens) {
+    final latest = _stats.latest;
+    if (latest == null) {
+      return ClideText('No activity recorded yet.', muted: true, fontSize: clideFontSmall);
+    }
+    return Column(
+      crossAxisAlignment: CrossAxisAlignment.start,
+      children: [
+        ClideText(latest.date, fontSize: clideFontSmall, color: tokens.globalForeground),
+        const SizedBox(height: 2),
+        ClideText(
+          '${latest.messageCount} msgs  ·  ${latest.sessionCount} sessions  ·  ${latest.toolCallCount} tools',
+          muted: true,
+          fontSize: clideFontSmall,
+        ),
+        const SizedBox(height: 6),
+        ClideText(
+          'Lifetime: ${_stats.lifetimeMessages} msgs over ${_stats.activeDays} days',
+          muted: true,
+          fontSize: clideFontSmall,
+        ),
+      ],
+    );
+  }
+
+  Widget _roster(SurfaceTokens tokens) {
+    if (_members.isEmpty) {
+      return ClideText('No team active.', muted: true, fontSize: clideFontSmall);
+    }
+    return Column(
+      crossAxisAlignment: CrossAxisAlignment.stretch,
+      children: [for (final m in _members) _memberRow(tokens, m)],
+    );
+  }
+
+  Widget _memberRow(SurfaceTokens tokens, TeamMemberJoined m) {
+    final color = teamColor(m.color, fallback: tokens.globalForeground);
+    final sub = [m.agentType, if (m.model != null) shortModelLabel(m.model!)].join('  ·  ');
+    return Padding(
+      padding: const EdgeInsets.symmetric(vertical: 4),
+      child: Row(
+        children: [
+          Container(width: 8, height: 8, decoration: BoxDecoration(color: color, shape: BoxShape.circle)),
+          const SizedBox(width: 8),
+          Expanded(
+            child: Column(
+              crossAxisAlignment: CrossAxisAlignment.start,
+              children: [
+                ClideText(m.name, fontSize: clideFontSmall, color: tokens.globalForeground, maxLines: 1, overflow: TextOverflow.ellipsis),
+                ClideText(sub, muted: true, fontSize: clideFontSmall, maxLines: 1, overflow: TextOverflow.ellipsis),
+              ],
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+}

lib/builtin/claude/src/claude_stats.dart

@@ -0,0 +1,68 @@
+/// Reads Claude Code's `~/.claude/stats-cache.json` — per-day activity
+/// (message / session / tool-call counts) — for the meta sidebar (T-141).
+/// Flutter-free so it unit-tests under `dart test`. This is activity, not the
+/// account budget; the budget isn't programmatically exposed (see
+/// project memory / GitHub anthropics/claude-code#44328).
+library;
+
+import 'dart:convert';
+
+class DailyActivity {
+  const DailyActivity({
+    required this.date,
+    required this.messageCount,
+    required this.sessionCount,
+    required this.toolCallCount,
+  });
+
+  final String date; // "YYYY-MM-DD" (sorts chronologically as a string)
+  final int messageCount;
+  final int sessionCount;
+  final int toolCallCount;
+}
+
+class ClaudeStats {
+  const ClaudeStats({this.lastComputed, this.daily = const []});
+
+  final String? lastComputed;
+  final List<DailyActivity> daily;
+
+  /// The most recent day on record, or null if there's no activity.
+  DailyActivity? get latest {
+    if (daily.isEmpty) return null;
+    return daily.reduce((a, b) => a.date.compareTo(b.date) >= 0 ? a : b);
+  }
+
+  int get activeDays => daily.length;
+  int get lifetimeMessages => daily.fold(0, (a, d) => a + d.messageCount);
+  int get lifetimeSessions => daily.fold(0, (a, d) => a + d.sessionCount);
+  int get lifetimeToolCalls => daily.fold(0, (a, d) => a + d.toolCallCount);
+}
+
+/// Parse the stats-cache JSON. Returns empty stats on any malformed input —
+/// the sidebar degrades to "no activity" rather than throwing.
+ClaudeStats parseClaudeStats(String jsonStr) {
+  Object? j;
+  try {
+    j = jsonDecode(jsonStr);
+  } catch (_) {
+    return const ClaudeStats();
+  }
+  if (j is! Map) return const ClaudeStats();
+  final daily = <DailyActivity>[];
+  final da = j['dailyActivity'];
+  if (da is List) {
+    for (final e in da) {
+      if (e is! Map) continue;
+      daily.add(DailyActivity(
+        date: '${e['date']}',
+        messageCount: _int(e['messageCount']),
+        sessionCount: _int(e['sessionCount']),
+        toolCallCount: _int(e['toolCallCount']),
+      ));
+    }
+  }
+  return ClaudeStats(lastComputed: j['lastComputedDate'] as String?, daily: daily);
+}
+
+int _int(Object? v) => v is num ? v.toInt() : 0;

lib/builtin/claude/src/extension.dart

@@ -6,6 +6,7 @@ import 'package:clide/builtin/claude/src/claude_config.dart';
 import 'package:clide/builtin/claude/src/claude_session_host.dart';
 import 'package:clide/builtin/claude/src/session_naming.dart';
 import 'package:clide/builtin/claude/src/pane_context_status.dart';
+import 'package:clide/builtin/claude/src/claude_meta_sidebar.dart';
 import 'package:clide/builtin/claude/src/session_index.dart';
 import 'package:clide/builtin/claude/src/session_storage.dart';
 import 'package:clide/builtin/claude/src/team_observer.dart';
@@ -13,6 +14,7 @@ import 'package:clide/builtin/claude/src/team_panel_host.dart';
 import 'package:clide/builtin/claude/src/tmux_session.dart' as tmux;
 import 'package:clide/extension/extension.dart';
 import 'package:clide/kernel/kernel.dart';
+import 'package:clide/widgets/widgets.dart';
 import 'package:flutter/widgets.dart';
 
 class ClaudeExtension extends ClideExtension {
@@ -68,6 +70,16 @@ class ClaudeExtension extends ClideExtension {
           title: 'Claude: session storage (disk usage + cleanup)',
           run: _manageStorage,
         ),
+        // Always-pickable left-panel tab: Claude activity (from
+        // stats-cache.json) + the team roster when a team is running (T-141).
+        TabContribution(
+          id: 'claude.meta',
+          slot: Slots.sidebar,
+          title: 'Activity',
+          icon: PhosphorIcons.robot,
+          priority: 60,
+          build: (_) => const ClaudeMetaSidebar(),
+        ),
         // In-pane status slot (T-145): the active Claude pane publishes
         // its model · permission-mode · context line here.
         StatusItemContribution(