feat: add per-agent logging UI and fix stuck agent issues

Changes:
- Add per-agent log viewer with copy-to-clipboard functionality
  - New AgentLogEntry type for structured log entries
  - Logs stored per-agent in WebSocket state (up to 500 entries)
  - Log modal rendered via React Portal to avoid overflow issues
  - Click log icon on agent card to view full activity history

- Fix agents getting stuck in "failed" state
  - Wrap client context manager in try/except (agent.py)
  - Remove failed agents from UI on error state (useWebSocket.ts)
  - Handle permanently failed features in get_all_complete()

- Add friendlier agent state labels
  - "Hit an issue" → "Trying plan B..."
  - "Retrying..." → "Being persistent..."
  - Softer colors (yellow/orange instead of red)

- Add scheduling scores for smarter feature ordering
  - compute_scheduling_scores() in dependency_resolver.py
  - Features that unblock others get higher priority

- Update CLAUDE.md with parallel mode documentation

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

ui/src/lib/types.ts

@@ -177,6 +177,13 @@ export type AgentMascot = typeof AGENT_MASCOTS[number]
 // Agent state for Mission Control
 export type AgentState = 'idle' | 'thinking' | 'working' | 'testing' | 'success' | 'error' | 'struggling'
 
+// Individual log entry for an agent
+export interface AgentLogEntry {
+  line: string
+  timestamp: string
+  type: 'output' | 'state_change' | 'error'
+}
+
 // Agent update from backend
 export interface ActiveAgent {
   agentIndex: number
@@ -186,6 +193,7 @@ export interface ActiveAgent {
   state: AgentState
   thought?: string
   timestamp: string
+  logs?: AgentLogEntry[]  // Per-agent log history
 }
 
 // WebSocket message types