Stage 3: Expand + Master Plan -- AgentOS Cognitive Synchronization

#### R1: Interrupt File Race Condition **Failure scenario**: PostToolUse hook and SessionEnd hook fire within milliseconds of each other for the same pane. Both try to write `/tmp/pane_interrupts/ttys007.json`. One overwrites the other. The SessionEnd signal (high priority) is lost because PostToolUse (low priority) clobbered it. **Probability**: Medium (hooks fire frequently, timing overlap is plausible) **Impact**: High (missed SIG_SESSION_END means the orchestrator thinks the pane is still working for up to 5 minutes) Each interrupt is a separate file. The orchestrator reads ALL files in the directory, sorts by timestamp, takes the highest-priority one, and deletes consumed files. **Validation**: Write a test that fires 100 concurrent interrupts to the same TTY directory and verifies zero data loss. #### R2: Drift Meter Threshold Produces False Positives at High Pane Count **Failure scenario**: With 40 panes, each emitting SIG_TOOL_ACTIVE (drift += 0.02), the aggregate drift noise triggers sync pulses continuously. The system enters a "sync storm" where every cycle fires a pulse, defeating the purpose of event-driven sync.