Harden .gitignore: broaden .env exclusion to *.env (with explicit exceptions for global.env and *.env-example templates), ignore stray .bak files

.gitignore

@@ -2,8 +2,17 @@
 *.swp
 *.swo
 .DS_Store
+
+# Secrets / stack env files - never commit these.
+# deploy/global.env and immich.env-example etc. are the intended committed
+# templates/examples; actual secret-bearing .env files must stay untracked.
 .env
 .env.local
+*.env
+!*.env-example
+!deploy/global.env
+*.env.bak
+*.env.backup
 secrets/
 keys/
 *.key
@@ -15,3 +24,7 @@ keys/
 # Local overrides
 docker-compose.override.yml
 local/
+
+# Editor/adhoc backups that sometimes get left in the tree
+*.bak
+*.bak-*