plex: pin image to 1.43.3.10828-ls316 (the exact running version)

Same PMS build the database was born on. SQLite schema upgrades are
one-way; a surprise :latest bump no longer gets a vote. Bump the pin
deliberately when choosing to upgrade.

plex/docker-compose.yml

@@ -1,10 +1,10 @@
 services:
   plex:
-    # Pin the tag. The migrated database is from PMS 1.43.3.10828 and SQLite
-    # schema upgrades are ONE-WAY — the server here must be equal or newer, and
-    # you do not want a surprise release performing an unexpected schema
-    # migration on build night. Set this to a concrete tag before first start.
-    image: lscr.io/linuxserver/plex:latest
+    # PINNED 2026-08-02 to the exact version running (and matching the migrated
+    # database — Windows also ran 1.43.3.10828, so no schema upgrade occurred).
+    # SQLite schema upgrades are ONE-WAY; upgrade by bumping this pin
+    # deliberately, never by riding :latest.
+    image: lscr.io/linuxserver/plex:1.43.3.10828-00f62d37d-ls316
     container_name: plex
     restart: unless-stopped