feat: add Claude usage tracking via CLI

Adds a Claude usage tracking feature that displays session, weekly, and Sonnet usage stats. Uses the Claude CLI's /usage command to fetch data (no API key required).

Features:
- Usage popover in board header showing session, weekly, and Sonnet limits
- Progress bars with color-coded status (green/orange/red)
- Auto-refresh with configurable interval
- Caching of usage data with stale indicator
- Settings section for refresh interval configuration

Server:
- ClaudeUsageService: Executes Claude CLI via PTY (expect) to fetch usage
- New /api/claude/usage endpoint

UI:
- ClaudeUsagePopover component with usage cards
- ClaudeUsageSection in settings for configuration
- Integration with app store for persistence

apps/ui/src/store/app-store.ts

@@ -507,6 +507,67 @@ export interface AppState {
     planContent: string;
     planningMode: "lite" | "spec" | "full";
   } | null;
+
+  // Claude Usage Tracking
+  claudeRefreshInterval: number; // Refresh interval in seconds (default: 60)
+  claudeUsage: ClaudeUsage | null;
+  claudeUsageLastUpdated: number | null;
+}
+
+// Claude Usage interface matching the server response
+export interface ClaudeUsage {
+  sessionTokensUsed: number;
+  sessionLimit: number;
+  sessionPercentage: number;
+  sessionResetTime: string;
+  sessionResetText: string;
+
+  weeklyTokensUsed: number;
+  weeklyLimit: number;
+  weeklyPercentage: number;
+  weeklyResetTime: string;
+  weeklyResetText: string;
+
+  opusWeeklyTokensUsed: number;
+  opusWeeklyPercentage: number;
+  opusResetText: string;
+
+  costUsed: number | null;
+  costLimit: number | null;
+  costCurrency: string | null;
+}
+
+/**
+ * Check if Claude usage is at its limit (any of: session >= 100%, weekly >= 100%, OR cost >= limit)
+ * Returns true if any limit is reached, meaning auto mode should pause feature pickup.
+ */
+export function isClaudeUsageAtLimit(claudeUsage: ClaudeUsage | null): boolean {
+  if (!claudeUsage) {
+    // No usage data available - don't block
+    return false;
+  }
+
+  // Check session limit (5-hour window)
+  if (claudeUsage.sessionPercentage >= 100) {
+    return true;
+  }
+
+  // Check weekly limit
+  if (claudeUsage.weeklyPercentage >= 100) {
+    return true;
+  }
+
+  // Check cost limit (if configured)
+  if (
+    claudeUsage.costLimit !== null &&
+    claudeUsage.costLimit > 0 &&
+    claudeUsage.costUsed !== null &&
+    claudeUsage.costUsed >= claudeUsage.costLimit
+  ) {
+    return true;
+  }
+
+  return false;
 }
 
 // Default background settings for board backgrounds
@@ -756,6 +817,11 @@ export interface AppActions {
     planningMode: "lite" | "spec" | "full";
   } | null) => void;
 
+  // Claude Usage Tracking actions
+  setClaudeRefreshInterval: (interval: number) => void;
+  setClaudeUsageLastUpdated: (timestamp: number) => void;
+  setClaudeUsage: (usage: ClaudeUsage | null) => void;
+
   // Reset
   reset: () => void;
 }
@@ -848,6 +914,9 @@ const initialState: AppState = {
   defaultRequirePlanApproval: false,
   defaultAIProfileId: null,
   pendingPlanApproval: null,
+  claudeRefreshInterval: 60,
+  claudeUsage: null,
+  claudeUsageLastUpdated: null,
 };
 
 export const useAppStore = create<AppState & AppActions>()(
@@ -2280,6 +2349,14 @@ export const useAppStore = create<AppState & AppActions>()(
       // Plan Approval actions
       setPendingPlanApproval: (approval) => set({ pendingPlanApproval: approval }),
 
+      // Claude Usage Tracking actions
+      setClaudeRefreshInterval: (interval: number) => set({ claudeRefreshInterval: interval }),
+      setClaudeUsageLastUpdated: (timestamp: number) => set({ claudeUsageLastUpdated: timestamp }),
+      setClaudeUsage: (usage: ClaudeUsage | null) => set({
+        claudeUsage: usage,
+        claudeUsageLastUpdated: usage ? Date.now() : null,
+      }),
+
       // Reset
       reset: () => set(initialState),
     }),
@@ -2352,6 +2429,10 @@ export const useAppStore = create<AppState & AppActions>()(
         defaultPlanningMode: state.defaultPlanningMode,
         defaultRequirePlanApproval: state.defaultRequirePlanApproval,
         defaultAIProfileId: state.defaultAIProfileId,
+        // Claude usage tracking
+        claudeUsage: state.claudeUsage,
+        claudeUsageLastUpdated: state.claudeUsageLastUpdated,
+        claudeRefreshInterval: state.claudeRefreshInterval,
       }),
     }
   )