refactor(agent-office): drop the random idle→break→idle cycle

The pixel-office game UI is gone, so simulating coffee-break /
nap / walk states no longer serves any purpose. Remove:
- scheduler's _check_idle_breaks job (no more 60s idle scan)
- BaseAgent.check_idle_break() and _break_until field
- 'break' from VALID_STATES and from transition() branches
- IDLE_BREAK_THRESHOLD / BREAK_DURATION_MIN / BREAK_DURATION_MAX
  config knobs
- 'idle/break' guard in each agent's on_schedule (now just 'idle')

Agents now sit in 'idle' between scheduled jobs and explicit
commands. Display reads 'Idle' instead of churning between idle
and break.

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

agent-office/app/config.py

@@ -26,11 +26,6 @@ CORS_ALLOW_ORIGINS = os.getenv(
     "CORS_ALLOW_ORIGINS", "http://localhost:3007,http://localhost:8080"
 )
 
-# Idle break threshold (seconds)
-IDLE_BREAK_THRESHOLD = int(os.getenv("IDLE_BREAK_THRESHOLD", "300"))  # 5 min
-BREAK_DURATION_MIN = int(os.getenv("BREAK_DURATION_MIN", "60"))       # 1 min
-BREAK_DURATION_MAX = int(os.getenv("BREAK_DURATION_MAX", "180"))      # 3 min
-
 # Lotto Curator
 LOTTO_BACKEND_URL = os.getenv("LOTTO_BACKEND_URL", "http://lotto:8000")
 LOTTO_CURATOR_MODEL = os.getenv("LOTTO_CURATOR_MODEL", "claude-sonnet-4-5")