Runner self-healing CI and dev stack initialization

Goal: a runner can heal its own CI and a local dev stack starts whole. - `jaah-forge run rerun` admits the runner's own `fleet/task-<id>` branch on a project with an empty branch prefix; every other branch stays refused. - The seeded dev node and its container agree on `jaah_home`, so slots materialise and the browser console attaches to a slot's real path. Out of scope: what a rerun may target beyond the runner's own branch. Done means: - A test in apps/jaahd/tests/test_forge_cli_policy.py pins the empty-prefix own-branch case. - A fresh `./dc up && ./dc seed --dev && ./dc --profile node up` logs no "could not materialise declared slot". - `./dc check quick` green.

run rerun now admits the runner's own fleet/task-<id> under an empty prefix (others refused, test pinned); dev-node container home now matches the seeded row, so slots materialise (0 failures live). Quick gate green, review lane passed, PR #7035 queued. Deferred: take the task id from the broker. Memory: used mem-25288.