chore: prettier format all files, brotli, Sentry release tagging, CI gates

Prettier: auto-formatted 103 files to fix baseline. Prettier check in CI
  is now a hard gate (removed continue-on-error).

Brotli: installed libnginx-mod-http-brotli-filter/static. Enabled in nginx
  with brotli_static on for pre-compressed assets and comp_level 6.

Sentry releases: deploy script now exports VITE_APP_VERSION=<git-short-sha>
  before building so each Sentry release maps to an exact commit.
  CI also passes github.sha as VITE_APP_VERSION.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.github/dependabot.yml

@@ -2,29 +2,29 @@
 
 version: 2
 updates:
-#   - package-ecosystem: npm
-#     directory: /
-#     schedule:
-#       interval: weekly
-#       day: "tuesday"
-#       time: "01:00"
-#       timezone: "Asia/Kolkata"
-#     open-pull-requests-limit: 15
+  #   - package-ecosystem: npm
+  #     directory: /
+  #     schedule:
+  #       interval: weekly
+  #       day: "tuesday"
+  #       time: "01:00"
+  #       timezone: "Asia/Kolkata"
+  #     open-pull-requests-limit: 15
 
   - package-ecosystem: github-actions
     directory: /
     schedule:
       interval: weekly
-      day: "tuesday"
-      time: "01:00"
-      timezone: "Asia/Kolkata"
+      day: 'tuesday'
+      time: '01:00'
+      timezone: 'Asia/Kolkata'
     open-pull-requests-limit: 5
 
   - package-ecosystem: docker
     directory: /
     schedule:
       interval: weekly
-      day: "tuesday"
-      time: "01:00"
-      timezone: "Asia/Kolkata"
+      day: 'tuesday'
+      time: '01:00'
+      timezone: 'Asia/Kolkata'
     open-pull-requests-limit: 5