Remove window duration telemetry from A2A wake messages

Context The bridge-daemon.mjs currently appends a Window: [X]ms footer to A2A wake digests. This telemetry was initially useful for verifying coalescing logic, but it now introduces unnecessary noise to the human-readable A2A notification channel.

The Problem A2A wake notifications contain Window: Xms, which clutters the notification and provides little actionable value for day-to-day swarm operations. The human operator identified this as redundant noise.

The Architectural Reality The flushSubscription function in ai/scripts/bridge-daemon.mjs computes windowDuration from coalesceState[subId].windowStart and appends it to the digest string.

The Fix

1. Remove windowStart from the coalesceState initialization in queueEvent (ai/scripts/bridge-daemon.mjs:417).
2. Remove const windowDuration = Date.now() - windowStart; from flushSubscription (ai/scripts/bridge-daemon.mjs:537).
3. Remove the \nWindow: ${windowDuration}ms suffix from the generated digest payload (ai/scripts/bridge-daemon.mjs:539).

Acceptance Criteria

• windowStart is removed from the bridge-daemon.mjs coalesceState.
• digest string no longer contains Window: [X]ms.
• Tests pass successfully.

Out of Scope

• Changes to the actual coalescing window logic (e.g. coalesceWindow settings).
• Removal of other metadata like Subscription: [ID].

Origin Session ID: d5ed6767-0292-46bf-9346-439f268048ec