docs(feature): cloud-served transcripts say the audio left the homelab; empty transcript also triggers the fallback (#52)

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

docs/homelab-integration.md

@@ -14,7 +14,8 @@ it** — endpoints and aliases drift, and this file is a snapshot (2026-06-06),
     not LiteLLM. Use `30401` for off-cluster LiteLLM. `confirm` resolved.
 - **Speech-to-text (ADR-033):** the same gateway serves `POST /v1/audio/transcriptions` for
   `iguana/kb-whisper` (primary, local) and `berget/kb-whisper` (fallback, EU cloud — private audio
-  leaves the homelab if it is used). **Call it via the NodePort / in-cluster address above, NOT
+  leaves the homelab if it is used: when the primary fails **or returns an empty transcript**,
+  e.g. a silent or music-only file; the transcript page then says so, #52). **Call it via the NodePort / in-cluster address above, NOT
   `https://llm-api.d-ma.be`:** that public ingress (openresty) returns `413` for bodies over
   roughly 8–10 MB (~5 minutes of 16 kHz WAV), while the NodePort took 174 MB (90 minutes) in one
   request (measured 2026-10-01, `docs/research/audio-length-ceiling-2026-10-01.md`). Send multipart

docs/use-cases/audio_upload.feature

@@ -240,6 +240,11 @@ Feature: Upload an audio recording, get a private Swedish transcript, discuss it
     Then it is transcribed anyway and its audio step says how long the audio really is
     And a complete recording whose header over-estimated its length is not refused
 
+  Scenario: A transcript made by the cloud fallback says the audio left the homelab
+    When the transcript was produced by an endpoint that is not local
+    Then its page says in plain words that the audio left the homelab and names the provider
+    And a locally transcribed recording carries no such note
+
   Scenario: A full queue is a retry, not an error
     When too many recordings are already waiting
     Then the upload is answered as busy, its row is failed honestly and its audio is deleted