release: v0.13.2 — PWA cache fix so mobile gets the v0.13.x modal

Mobile operators were never seeing the inline PDF preview, .TXT
download, or Review form that v0.13.0 added — every feature was
working on desktop browsers but invisible in the PWA.

Root cause: backend/static/sw.js had CACHE_VERSION = 'v1', unchanged
since v0.12.x.  The activate handler deletes any cache not matching
CACHE_VERSION, so without a bump the stale sfm-static-v1 cache (with
the pre-v0.13.0 event-modal.js) stayed authoritative.  cacheFirst
strategy served it forever; mobile users effectively saw the v0.12.x
modal regardless of how many times we rebuilt the image.

Fix:
- CACHE_VERSION bumped to 'v0.13.2' (matches backend/main.py VERSION).
  Comment in sw.js documents the convention: any release touching a
  static asset must bump this string.
- event-modal.js added to the precache list so its lifecycle is
  explicitly tied to the SW version bump (installed fresh on activate
  rather than landing via the cacheFirst-then-cached pattern).

Mobile users get the new modal on next page nav: SW update check
picks up the bumped sw.js, skipWaiting installs it, activate evicts
the v1 caches, controllerchange fires, page reloads, fresh
event-modal.js loads.  Worst case ~1h delay from
registration.update() interval; operators can force-refresh by
closing + reopening the PWA.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

README.md

@@ -1,4 +1,4 @@
-# Terra-View v0.13.1
+# Terra-View v0.13.2
 Backend API and HTMX-powered web interface for managing a mixed fleet of seismographs and field modems. Track deployments, monitor health in real time, merge roster intent with incoming telemetry, and control your fleet through a unified database and dashboard.
 
 ## Features