Bound collision subscription scans to a 30s timestamp window

Each collision subscription ran a correlated EXISTS that SQLite drove through
idx_type, walking every status event (~0.3s per subscription) on every
file-write status event, inside the writing agent's PreToolUse hook. Range on
the ISO timestamp so idx_timestamp is used and keep ABS for the exact window.
Stored collision subscriptions are upgraded in place on next evaluation (only
the sql field, only if the record is unchanged since it was read).