Fail loudly when release uploads do not land

Follow-up to the publishing fix: CI created the v0.2.11 release and logged each
upload, but the assets never arrived, so the job looked successful while the
release was empty. The host root filesystem is full (7.8G, 100%), and Gitea
answered HTTP 500 "Attachments.Save: no space left on device".

- publish_release.sh now checks the HTTP status of every asset upload and prints the
  response body on failure, then verifies the release reports as many assets as were
  sent. Empty releases can no longer pass silently.
- Deleted the empty v0.2.11 release so the "latest" release (v0.2.10) still has all
  five artifacts; the tag itself remains.
- TODO/MEMORY record the host disk blocker with concrete cleanup commands and note
  that v0.2.11 artifacts are built locally in build/ for upload once space exists.

TODO.md

@@ -33,7 +33,16 @@ Verified via API+host credentials (2026-10-31):
       `GITEA_TOKEN` secret).
 - [x] Fall back to the checkout's git extraheader when no token/credentials exist (the
       Gitea runner does not expose `github.token`).
-- [ ] Verify the fallback on the next tag push produces a release automatically.
+- [x] Uploads now fail loudly and the release is verified to carry every artifact
+      (a silent HTTP 4xx used to leave an empty release with a green job).
+- [ ] **Host disk is full** (`/` 7.8G, 100%, 0 bytes free) so release uploads fail with
+      HTTP 500 `Attachments.Save: no space left on device`. Root-owned data is using the
+      space; `sudo journalctl --vacuum-size=100M` (~700 MB in `/var/log/journal`),
+      `sudo apt-get clean` (~90 MB), and clearing `attachments/tmp` would unblock it.
+      Alternative: prune superseded releases (v0.2.0 + v0.2.9 assets ≈ 565 MB).
+- [ ] Verify the fallback on the next tag push produces a release automatically (the
+      v0.2.11 tag build reached the publish step and created the release; only the
+      upload failed on disk space).
 - [ ] Optionally backfill releases for v0.2.4–v0.2.8 (their CI artifacts were not
       retained; would need local rebuilds) or leave them superseded by the latest.