Release 1.0.18 Plan gate, Task Notes, new models

Added

Plan Gate: interactive tasks get a read-only planning run and an Approve/Reject card. An approved plan’s file list becomes the PR-preflight allow-list. A rejected or timed-out plan blocks the task.
Task Notes: post notes to a running task from the Notes panel or with Telegram /reply. Each note is delivered once, into the next attempt.
Models: Claude Haiku 5.5 and Gemini 4 Argon (High, Medium and Low).

Changed

Model IDs now live in one typed registry. The web app reads it, cached for 60s.
Models two or more generations old are hidden from the pickers. Stored IDs still work.

Fixed
Cancel now kills the agent process group and always ends in a terminal status.
Repo locks are owned leases with a TTL and a heartbeat.
A task on a busy repo is re-queued instead of failing.
Stale recovery only touches tasks with no live lock.
All git calls have timeouts.
The runner no longer holds a DB session for the whole run.
PR preflight hard failures are no longer retried on the backup model.
Compaction summaries are now used on the next run.
Fixed a crash in the side-effect gate.
The task log endpoint now rejects path traversal.