feat(ai): narrow the auto-read consent and refuse the connection test with AI off

Turning document auto-read on now mints an ai_extraction receipt instead
of ai_full, so it covers reading documents, lab reports and medication
text and no longer opens the Coach or the AI analysis. Receipts minted as
ai_full by earlier releases stay valid. The catch-up over stored
documents is only scheduled while documentAi is open for the record.

The AI connection test is an AI call, so it is refused with
assistant.disabled.enabled while the operator's master switch is off, and
fails closed with ai.unavailable when the switches cannot be read (403,
since the route never answers 5xx). A missing provider carries
ai.provider.none and a spent daily budget ai.budget.exceeded.

src/lib/openapi/error-codes.ts

@@ -38,7 +38,12 @@
  */
 export const ERROR_CODE_CATALOGUE: Readonly<Record<string, readonly string[]>> =
   {
-    ai: ["ai.provider.none", "ai.record.notPermitted", "ai.unavailable"],
+    ai: [
+      "ai.budget.exceeded",
+      "ai.provider.none",
+      "ai.record.notPermitted",
+      "ai.unavailable",
+    ],
     ai_provider: ["ai_provider.invalid", "ai_provider.no_fields"],
     allergy: ["allergy.invalid"],
     analytics: ["analytics.invalid_query"],
@@ -62,6 +67,7 @@ export const ERROR_CODE_CATALOGUE: Readonly<Record<string, readonly string[]>> =
     ],
     backup: ["backup.payload.undecryptable", "backup.section.missing"],
     coach: [
+      "coach.budget.exceeded",
       "coach.conversation.invalidTitle",
       "coach.conversation.notFound",
       "coach.fenced.attachmentConflict",