fix(test): close the test-entry leak into real trip content

A ui-test entry had survived into the active trip's dailies. Three independent
failures had to line up for that, and all three were real:

1. cleanupEntry() used host-side fs.rmSync. Grav's Apache workers run as root,
   so every entry the form creates is root-owned and recursive removal needs
   write permission on that directory — which the host user lacks. Cleanup had
   never worked for form-created entries; it just threw inside a path nothing
   checked. It now falls back to `docker exec … rm -rf` in the container that
   actually serves USER_DIR.

2. globalTeardown's dailies sweep keyed off a `parent:` in post-form.md — a key
   deliberately removed (the write target comes from site.yaml active_trip, and
   CLAUDE.md forbids re-adding a static parent). The regex could never match, so
   dailiesDir was always null and the sweep silently did nothing. It now reuses
   helpers' own resolution instead of keeping a divergent copy.

3. Nothing pinned the suite to this checkout's server. playwright.config.js
   defaults to :8081, so a worktree run hit the MAIN checkout — entries created
   in one content tree while the specs asserted and cleaned up in another.
   test-ui now passes GRAV_BASE_URL from GRAV_PORT, and globalSetup hard-fails
   when the server's bind mount disagrees with the tree the specs read.

Also fixed, found on the way to a green run:

- test-account interpolated the password into an `sh -c` string, so a password
  containing a shell metacharacter was re-parsed by the container's shell
  (`sh: 2: <fragment>: not found`, no account, every UI run dead). It now
  travels via `docker exec -e`, making the recipe indifferent to its contents.
- `make start` in a worktree always failed: travel-memories declares
  `env_file: .env` and worktree-new creates none. It degrades to start-grav
  there — a worktree with no server is what sent runs to :8081 in the first
  place.
- test-form-config asserted a hero_image field that 8cf1145 deliberately
  removed; it had been failing ever since.

Verified: config 22/22, post 6/6, location-override 20/20, and a full UI run
now leaves zero ui-test entries behind. The remaining UI failures are
pre-existing on main — site.yaml pins owner_username to a real account while
the suite logs in as testrunner, so owner-only controls never render for it.
Only trip-publish.spec.js patches that; delete-flow, edit-mode and anon-view
do not. Left for a separate branch.

scripts/test-form-config.sh

@@ -59,7 +59,10 @@ check_grep "location_country field present" "name: location_country"
 check_grep "weather_desc field present"     "name: weather_desc"
 check_grep "weather_temp_c field present"   "name: weather_temp_c"
 check_grep "transport_mode field present"   "name: transport_mode"
-check_grep "hero_image field present"       "name: hero_image"
+# No hero_image assertion: the field was deliberately dropped in 8cf1145 —
+# entries render their hero from the first photo, so an explicit filename was
+# redundant (see the comment at that spot in post-form.md). This check outlived
+# the field and had been failing ever since.
 check_grep "force_connect field present"    "name: force_connect"
 check_grep "featured field present"         "name: featured"