build(intake): give the container an ANTHROPIC_API_KEY (#223)

The drafting worker needs a credential, and a Portainer stack variable alone does not reach the container — stack variables are interpolated into the compose file as ${VAR}, and a service receives exactly what its own environment block lists. That is how UPLOADS_DIR went missing in #118, and both files say so; this adds the line that makes the variable actually arrive.

QA takes it from QA_ANTHROPIC_API_KEY, prefixed like the database and SMTP credentials so production's key cannot be pasted there and silently work. It is also worth a key of its own rather than sharing production's, because this is the only credential in either stack that spends money per call, on a path anybody holding an upload link can trigger.

Absent is a working configuration in both, deliberately, which is why prod's line carries `:-` and neither variable joins the always-required list. A submission still arrives, keeps its photos and waits undrafted. Losing somebody's consignment to an expired key would be far worse than an item arriving without its description written, and the photos may be the only copy of something no longer in the sender's hands. USPS is the existing precedent for a credential whose absence degrades rather than fails.

The comments say plainly that a spend limit belongs on the key in the Anthropic console, since nothing in this repository can enforce one and #227's submission ceiling bounds the volume rather than the bill.

docs/ops/production-stack-cutover.md said the compose file interpolates thirteen names and listed them. It now says fourteen, because that document stakes its usefulness on being checked against the file rather than written from memory — a cutover working from a stale list is how a variable gets left behind, which is the failure the document exists to prevent. Counted from the file: exactly fourteen.

composeEnvironment.test.ts passes, 24 tests. It checks that every deployment sets what the validator requires, so adding a variable ahead of a validator entry cannot break it — the entry itself comes with the worker.

Ref #223

docs/ops/production-stack-cutover.md

@@ -60,7 +60,7 @@ Everything here is lost when the stack is deleted, and the rollback in step 8 is
 
 **The stack name**, exactly as Portainer shows it. If it is not `redefined-designs`, note that — the new stack must be created with that name, because the stack name becomes the compose project name and reusing QA's would make Compose reconcile the two against each other.
 
-**Every stack environment variable, name and value.** They belong to the stack, and deleting it discards them. This is the step whose omission is felt hardest. The compose file interpolates thirteen names — `DEMO_MODE`, `DB_PASSWORD`, `SMTP_USER`, `SMTP_PASSWORD`, `SMTP_FROM`, `ADMIN_GATE_SECRET`, `PAYPAL_CLIENT_ID`, `PAYPAL_CLIENT_SECRET`, `PAYPAL_WEBHOOK_ID`, `USPS_CLIENT_ID`, `USPS_CLIENT_SECRET`, `UPLOADS_BASE_URL` and `BACKUP_PASSPHRASE` — and an unset one substitutes to an empty string rather than failing. None of it is recoverable from anything in this repository. Take everything the stack holds rather than working from this list; it is here to say how much there is, and it is checked against the file rather than from memory.
+**Every stack environment variable, name and value.** They belong to the stack, and deleting it discards them. This is the step whose omission is felt hardest. The compose file interpolates fourteen names — `DEMO_MODE`, `DB_PASSWORD`, `SMTP_USER`, `SMTP_PASSWORD`, `SMTP_FROM`, `ADMIN_GATE_SECRET`, `PAYPAL_CLIENT_ID`, `PAYPAL_CLIENT_SECRET`, `PAYPAL_WEBHOOK_ID`, `USPS_CLIENT_ID`, `USPS_CLIENT_SECRET`, `UPLOADS_BASE_URL`, `BACKUP_PASSPHRASE` and `ANTHROPIC_API_KEY` — and an unset one substitutes to an empty string rather than failing. None of it is recoverable from anything in this repository. Take everything the stack holds rather than working from this list; it is here to say how much there is, and it is checked against the file rather than from memory.
 
 `USPS_CLIENT_ID` and `USPS_CLIENT_SECRET` deserve naming because losing them is the one failure here that is completely silent. Address validation is skipped when they are empty rather than failing, so checkout keeps working and quietly stops validating addresses. Nothing in step 7 catches it, and there is no crash loop to notice.