fix: v0.9.1 robustness cleanups

- run_resume falls back to a new conversation only when the transcript file
  is gone; other failures end at the menu with the recorded id intact.
- The SessionStart hook resolves the session name under the registry lock;
  rename holds it across tmux rename-session and the registry move
  (dd_registry_locked, nestable).
- dd_load_env parses KEY=value like systemd instead of sourcing the files.
- devdesk-deploy: DPkg::Lock::Timeout, explicit FAILED lines on stdout and in
  the log; the hook answers synchronously and CI checks the HTTP status.
  logrotate for the deploy log.
- postinst drops duplicate terminal-features entries; hooks sweep stale
  temp files.

Closes #12

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

.gitea/workflows/build-deb.yml

@@ -157,6 +157,8 @@ jobs:
     steps:
       # CT 126's webhook listener runs /usr/lib/devdesk/devdesk-deploy, which
       # waits for this version in the apt registry and upgrades the package.
+      # The hook answers when the install is done (HTTP 500 if it failed), so
+      # this job's result is the deploy's result.
       - name: Trigger devdesk-deploy webhook
         env:
           WEBHOOK_SECRET: ${{ secrets.WEBHOOK_SECRET }}
@@ -164,12 +166,15 @@ jobs:
         run: |
           PAYLOAD="{\"ref\":\"${GIT_REF}\"}"
           SIG=$(echo -n "$PAYLOAD" | openssl dgst -sha256 -hmac "$WEBHOOK_SECRET" | awk '{print $2}')
-          curl -sf --connect-timeout 10 \
+          code=$(curl -sS --connect-timeout 10 --max-time 900 -o /tmp/deploy.out -w '%{http_code}' \
             -X POST \
             -H "Content-Type: application/json" \
             -H "X-Gitea-Signature: ${SIG}" \
             -d "$PAYLOAD" \
-            "http://10.10.10.58:9000/hooks/devdesk-deploy"
+            "http://10.10.10.58:9000/hooks/devdesk-deploy") || code=000
+          cat /tmp/deploy.out 2>/dev/null || true
+          echo "webhook: HTTP $code"
+          [ "$code" = 200 ]
 
   notify-failure:
     name: Notify on failure