chore: release signage 0.1.2

0.1.2 fixes what the first production Signage deployment found:
- #4: the display and server share one message schema; every heartbeat
  from an image slide used to be refused with a 400;
- #5: every display request retries with backoff and never gives up, so
  a display that failed one request no longer stays offline until
  reloaded;
- #6: one object URL per cached slide, released when done; the leak
  exhausted the browser within minutes;
- CI (#7, #8): every change runs inside a pinned Ekklesia, end to end
  in a real browser, and cleans up even when killed.

compatibility.platform stays ^0.1.0: every fix is module-side, and CI
tested it against platform v0.1.1 plus test-only scripts. The README no
longer says Signage is unreleased or undeployed.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

README.md

@@ -16,7 +16,8 @@ Ekklesia and vendors none of its SDKs.
 
 ## Status
 
-Version 0.1.1 is feature-complete for its declared scope and unreleased. What exists today:
+Version 0.1.2 is feature-complete for its declared scope, and Signage has run in production since
+0.1.1. What exists today:
 
 - The module package, manifest (v7), four capabilities, six permissions, ten operator settings, and
   one logical storage bucket.
@@ -34,10 +35,10 @@ Version 0.1.1 is feature-complete for its declared scope and unreleased. What ex
   renderers mounted as browser contributions, the built-in "Content unavailable" slate, deliberate
   blackout, and offline continuation from this display's own persisted state.
 
-Nothing here is deployed, and no cutover from the legacy Announcements container has happened or is
-planned by this repository. Video, audio, MQTT, Home Assistant, Companion, and a notification outbox
-are out of scope; so is any content module — Signage ships with no announcements, scripture, or
-trivia, and cannot render any until one is installed.
+No cutover from the legacy Announcements container has happened or is planned by this repository.
+Video, audio, MQTT, Home Assistant, Companion, and a notification outbox are out of scope; so is
+any content module — Signage ships with no announcements, scripture, or trivia, and cannot render
+any until one is installed.
 
 ### Offline cold start is not yet possible