merge origin/main into feat/wf5-securestorage

Brings MOSAIC_GIT_IDENTITY (per-seat git authorship) onto the delivery
branch, which had none of it. The branch carried W-F7's FLEET_SEAT seam in
the same launcher file; the two auto-merged cleanly.

Three single-hunk conflicts resolved:
- pr-merge.sh: kept branch policy allowing main OR next (next is the
  release stream).
- test-ci-queue-wait-tristate.sh: kept the branch's 4 added merge-readiness
  assertions; merge base and main both had zero, so nothing of main's is
  reverted.
- package.json test:framework-shell: union of both enumerations, 50 entries,
  no test dropped from either side. Picks up main's test-start-agent-session.sh
  and test-fleet-units.sh, which are the guards for the identity key.

README.md

@@ -74,6 +74,14 @@ The launcher verifies your config, checks for `SOUL.md`, injects your `AGENTS.md
 
 Pi launches default to a token-lean skill posture: `mosaic pi` passes `--no-skills` so Pi does not preload every global skill description into the system prompt. Use `MOSAIC_PI_SKILL_MODE=all mosaic pi` for the legacy all-skills catalog, or `MOSAIC_PI_SKILL_MODE=discover mosaic pi` to let Pi use its native settings/project skill discovery.
 
+Mosaic also loads its Pi extensions from `~/.config/mosaic/runtime/pi/`. Inside Pi,
+`/goal set <statement>` starts a bounded persistent loop that checks every turn and successful
+compaction, requires two evidence-bearing completion reports, and can be inspected or stopped with
+`/goal status`, `/goal pause`, `/goal resume`, and `/goal cancel`. Controller-owned goal-state
+entries redact common credential shapes, but Pi's model/tool-call history is separate, so goals and
+evidence must never contain secrets or raw sensitive output. Mosaic does not install this extension
+into `~/.pi/agent/extensions/`.
+
 ### TUI & Gateway
 
 ```bash