chore(release): v0.12.2

Two download fixes since v0.12.1: transfers longer than five minutes were
being cut off by a total request deadline and restarted from zero, and the
progress bar read "0%" for the whole of a transcode download.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -9,6 +9,39 @@ generated trace matrix lives in [docs/traceability.md](docs/traceability.md).
 For how long each fixed defect had been shipping before it was found, see
 [docs/defect-windows.md](docs/defect-windows.md).
 
+## v0.12.2
+
+Two download fixes, found together on a tablet whose films all needed their
+audio re-encoded. Downloads that took longer than five minutes were being cut
+off and restarted, and the progress bar sat on "0%" for the whole of a
+transcode.
+
+### 🐛 Fixes
+
+- **Downloads longer than five minutes no longer fail.** The download worker's
+  HTTP client carried a *total* request deadline of five minutes — from
+  connect until the last byte — so every transfer longer than that was cut off
+  mid-body and retried. A transcode cannot be resumed (the server ignores
+  `Range` and starts over), so each retry threw away what had been fetched, hit
+  the same deadline, and after three attempts the download failed. No feature
+  film at transcode speed could complete; a large direct copy limped through in
+  five-minute slices with a backoff between each. The deadline is now a
+  30-second connect timeout plus a 60-second *stall* timeout that resets on
+  every chunk: a dead connection is still caught, a healthy transfer can run as
+  long as it needs. Present since the first release. (DR-289)
+
+### ✨ Improvements
+
+- **The progress bar moves during a transcode download.** A transcode is
+  produced as it is sent, with no `Content-Length`, and the bar had nothing to
+  measure against — it read "0%" until the file completed. The backend now
+  predicts the size when it resolves the download: the source's size for
+  `original` (the picture is copied byte-for-byte; only the audio changes), or
+  bitrate × runtime for a quality preset. The bar shows the estimate as
+  "~42%" and caps at 99% until the last byte lands; the server's own figure is
+  used whenever it gives one; and when there is no prediction at all the bar
+  is a moving band with the bytes so far, rather than a false "0%". (DR-290)
+
 ## v0.12.1
 
 One change: the TLS library every connection to the server goes through has a