fix(dispatch): background starter passes --repo to both order verbs

A background child runs in a worktree, and without --repo the order
verbs derive identity from the git toplevel's basename - the worktree's
name, not the repo's. Measured in the session that built the form: the
claim ran before the worktree and won; coord-order-done ran inside it and
exited 1 "no claimed order ... for dispatch-bg-form", leaving the order in
flight until --repo repo-mailbox was passed. The order's own starter
template carried the same defect.

§19b gains two checks (red against 24adf59, same predicate), the
template passes --repo <repo> to claim and done, and the skill says why.

Suites under bash 3.2: coord 257, board 495, route 73, orders 116,
guard 54 = 995. npm test 12/12.

Order 20260923T070445Z-9974217048-from-.claude (follow-up to 24adf59).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -14,7 +14,7 @@ Session A in repo X leaves a message for repo Y; the next session in repo Y gets
 ![Hooks](https://img.shields.io/badge/hooks-1-green)
 ![Skills](https://img.shields.io/badge/skills-4-orange)
 ![CLI scripts](https://img.shields.io/badge/CLI_scripts-8-blue)
-![Selftest checks](https://img.shields.io/badge/selftest_checks-993-blue)
+![Selftest checks](https://img.shields.io/badge/selftest_checks-995-blue)
 
 ---
 
@@ -203,7 +203,7 @@ Note that raising the inbox's priority (Rule 7) deliberately does **not** widen
 ## Development
 
     bash scripts/coord-selftest.sh              # 257 checks against a throwaway mailbox
-    bash scripts/board-selftest.sh              # 493 checks against a throwaway repo tree
+    bash scripts/board-selftest.sh              # 495 checks against a throwaway repo tree
     bash scripts/route-selftest.sh              # 73 checks, incl. the route->board round trip
     bash scripts/orders-selftest.sh             # 116 checks, incl. the 20-way barriered claim race
     bash scripts/state-line-guard-selftest.sh   # 54 checks, incl. the Edit replace_all projection and the ratchet