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/web/uploads_logging_handler_test.go

@@ -0,0 +1,72 @@
+package web_test
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"io"
+	"log/slog"
+	"net/http"
+	"net/url"
+	"sync"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// Error paths of the upload routes log a kind, never the error's text, which can carry
+// a file name, a path, a database value or a provider's output (adversarial review F5).
+
+type lockedBuf struct {
+	mu sync.Mutex
+	b  bytes.Buffer
+}
+
+func (l *lockedBuf) Write(p []byte) (int, error) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	return l.b.Write(p)
+}
+
+func (l *lockedBuf) String() string {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	return l.b.String()
+}
+
+type failingUploader struct{ err error }
+
+func (f failingUploader) Accept(context.Context, string, string, io.Reader) (string, error) {
+	return "", f.err
+}
+
+func TestUploadPost_AnUnexpectedFailureLogsAKindAndNotItsText(t *testing.T) {
+	app, _ := newUploadApp(t, audioOK, 200<<20)
+	buf := &lockedBuf{}
+	app.Log = slog.New(slog.NewTextHandler(buf, nil))
+	app.Uploads = failingUploader{err: errors.New(`ffprobe: Error opening input file /spool/upload-555 for "zebrakaka-meeting.m4a"`)}
+
+	rec := do(t, app, uploadReq(t, "t", "zebrakaka-meeting.m4a", []byte("x")))
+
+	assert.Equal(t, http.StatusInternalServerError, rec.Code)
+	out := buf.String()
+	assert.NotContains(t, out, "zebrakaka", "a file name is private content")
+	assert.NotContains(t, out, "/spool/", "a spool path carries the upload's identity")
+	assert.Contains(t, out, "kind=error")
+}
+
+func TestUploadChatPost_AModelFailureLogsAKindAndNotItsText(t *testing.T) {
+	app, fc := newUploadChatApp(t)
+	buf := &lockedBuf{}
+	app.Log = slog.New(slog.NewTextHandler(buf, nil))
+	fc.err = errors.New("LLM returned 400: the prompt was zebrakaka secret words")
+	id := seedUpload(t, userID, "m", "done", meetingText)
+
+	rec := do(t, app, chatPost("/uploads/"+id+"/chat", url.Values{"question": {"q"}}))
+
+	require.Equal(t, http.StatusOK, rec.Code)
+	out := buf.String()
+	assert.NotContains(t, out, "zebrakaka")
+	assert.Contains(t, out, "kind=error")
+}