feat: upload audio, get a private Swedish transcript, discuss it (#33, ADR-033) (#39)

Upload a recording (audio, or video with the camera off), get a private Swedish transcript, and chat about it.

- ADR-033: RLS-scoped private transcript store; ffprobe/ffmpeg intake; gateway transcription (iguana kb-whisper, berget fallback); in-process single-replica worker; chat over the transcript (local models only).
- ADR-034: optional two-engine mode (pianissimo + kb-whisper) reconciled by a LOCAL model; off unless TAPIR_RECONCILE_BASE_MODEL is set.
- ADR-035: real progress (phases, running/quiet/lost), phase logging, every judged spot stored, merged segments.
- Hardening from four adversarial reviews: errors logged and stored as kinds never text; per-engine deadlines; converted-length check; bounded queue; client hang-ups are not errors; strict local-alias check.
- Dockerfile: static ffmpeg/ffprobe 7.0.2 pinned by sha256 (#34). Built and inspected by hand; CI does not build the image on a PR, so its first CI build is this merge.

Uploads stay OFF until TAPIR_UPLOADS_ENABLED is set in the deployment.

Closes #33, #34, #42, #43, #44.

Co-authored-by: Mathias <mthbqv@gmail.com>

internal/adapters/chat/chat.go

@@ -41,6 +41,11 @@ type Request struct {
 	Transcript string
 	History    []Turn
 	Question   string
+	// MaxChars, when positive, overrides the Service's transcript budget for this
+	// request. The Service default is sized for YouTube captions (~22 minutes of
+	// speech); an uploaded recording is much longer, and truncation keeps only the
+	// head (ADR-033). Zero or negative means "use the Service default".
+	MaxChars int
 }
 
 // Reply is the model's answer plus whether the transcript was bounded to fit the
@@ -113,7 +118,11 @@ func (s *Service) Answer(ctx context.Context, req Request) (Reply, error) {
 		model = s.DefaultModel("")
 	}
 
-	transcript, truncated := truncate(req.Transcript, s.maxChars)
+	budget := s.maxChars
+	if req.MaxChars > 0 {
+		budget = req.MaxChars
+	}
+	transcript, truncated := truncate(req.Transcript, budget)
 	system := buildSystem(transcript, truncated)
 	user := buildUser(req.History, req.Question)