Remove dead translations and comments about a former design, and move the Orchestra bridges under yoyaku_orchestra

Problem/Motivation

Three leftovers found while doing #3616250: Declare every module whose classes a submodule names, none of them worth holding that issue open for, all of them the same kind of thing: the code says something that is no longer true, or sits somewhere that will cost later.

1. Comments describing a design that is gone

Yoyaku is pre-1.0 and documents the CURRENT design; there is no install base to explain a change to. Sixteen comments in shipped code still narrate a previous one ("There used to be two", "it used to have no home", "The calendar feed used to hold its own copy"), in src/AvailabilityCacheTags.php, src/ConstraintPolicyInterface.php, src/ConstraintPolicyManager.php, src/PolicyContext.php, src/TransactionLookup.php, src/Hook/BookingHooks.php, yoyaku_calendar/js/offers.js, yoyaku_orchestra (2), yoyaku_payment/src/Hook/BookingPaymentHooks.php and yoyaku_placement (5). Twenty-one more are in tests and stay: there "it used to be X" names the defect the test pins, which is what the test is for.

2. Dead entries in the French translation

Three msgids in translations/yoyaku.fr.po whose source string appears nowhere in the tree: "Place given as a last resort", its long description "Whether the seating reached this place only after every arrangement...", and the venue import message "Venue "@label" (id @id): @differ row(s) carry breaks...". The first two are a placement field that no longer exists.

3. The Orchestra bridges cannot be lifted out in one move

Extracting everything Orchestra from Yoyaku one day means gathering it from four places: yoyaku_payment_orchestra, yoyaku_cart_orchestra and yoyaku_ticket_orchestra each live under the module they extend, while yoyaku_orchestra_order and the new yoyaku_orchestra_manager live under yoyaku_orchestra. A bridge under its subject also strands an Orchestra-dependent module inside Yoyaku when Orchestra leaves.

Proposed resolution

Reword each comment to describe what the code does now, dropping the history. Delete the three dead msgids. Move the three bridges to yoyaku_orchestra/modules/ as yoyaku_orchestra_payment, yoyaku_orchestra_cart and yoyaku_orchestra_ticket, so every Orchestra integration sits under one directory and the rename costs nothing before 1.0.

Remaining tasks

• Add the orphan check to the release routine, normalizing apostrophes: a YAML single-quoted scalar doubles them, so a literal search reports live strings as dead (it reported six here, three were live).

AI-Generated: Yes (Claude Code was used to help draft this issue summary and to find the leftovers it reports. I reviewed it before posting; there is no code on this issue yet.)