feat(static-assets): cache-bust JS/CSS via ?v=<commit-sha>, immutable in prod

Adds a `static_v(request, name, path=...)` Jinja helper that appends
?v=<commit-sha> from app.core.build_info, plus a CachedStaticFiles
subclass that serves Cache-Control: public, max-age=31536000, immutable
in production and no-cache in development. Browsers refetch JS/CSS
automatically on every deploy without the user having to hard-reload.

- New: app/core/static_files.py (CachedStaticFiles)
- Updated: app/templates_config.py (static_v helper)
- Updated: main.py (use CachedStaticFiles for *_static mounts)
- Codemod: 143 url_for('*_static', path='*.js'|'*.css') → static_v(...)
  across 123 templates. Images/fonts/JSON locales intentionally
  unchanged (out of scope).
- Arch rule: FE-024 (warning) flags raw url_for on JS/CSS to prevent
  drift. Note: FE-008 was already taken by the number_stepper rule.
- docs/proposals/static-asset-cache-busting.md marked Done.

Closes plan from docs/proposals/static-asset-cache-busting.md.

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

app/modules/dev_tools/templates/dev_tools/admin/code-quality-dashboard.html

@@ -9,7 +9,7 @@
 {% block alpine_data %}codeQualityDashboard(){% endblock %}
 
 {% block extra_scripts %}
-<script defer src="{{ url_for('dev_tools_static', path='admin/js/code-quality-dashboard.js') }}"></script>
+<script defer src="{{ static_v(request, 'dev_tools_static', path='admin/js/code-quality-dashboard.js') }}"></script>
 {% endblock %}
 
 {% block content %}

app/modules/dev_tools/templates/dev_tools/admin/code-quality-violations.html

@@ -10,7 +10,7 @@
 {% block alpine_data %}codeQualityViolations(){% endblock %}
 
 {% block extra_scripts %}
-<script defer src="{{ url_for('dev_tools_static', path='admin/js/code-quality-violations.js') }}"></script>
+<script defer src="{{ static_v(request, 'dev_tools_static', path='admin/js/code-quality-violations.js') }}"></script>
 {% endblock %}
 
 {% block content %}

app/modules/dev_tools/templates/dev_tools/admin/components.html

@@ -3173,5 +3173,5 @@ new Chart(document.getElementById('barChart'), barConfig);
 
 {% block extra_scripts %}
 {# ✅ CRITICAL: Load JavaScript file #}
-<script defer src="{{ url_for('dev_tools_static', path='admin/js/components.js') }}"></script>
+<script defer src="{{ static_v(request, 'dev_tools_static', path='admin/js/components.js') }}"></script>
 {% endblock %}

app/modules/dev_tools/templates/dev_tools/admin/icons.html

@@ -318,5 +318,5 @@
 
 {% block extra_scripts %}
 {# ✅ CRITICAL: Load JavaScript file #}
-<script defer src="{{ url_for('dev_tools_static', path='admin/js/icons-page.js') }}"></script>
+<script defer src="{{ static_v(request, 'dev_tools_static', path='admin/js/icons-page.js') }}"></script>
 {% endblock %}

app/modules/dev_tools/templates/dev_tools/admin/sql-query.html

@@ -274,5 +274,5 @@
 {% endblock %}
 
 {% block extra_scripts %}
-<script defer src="{{ url_for('dev_tools_static', path='admin/js/sql-query.js') }}"></script>
+<script defer src="{{ static_v(request, 'dev_tools_static', path='admin/js/sql-query.js') }}"></script>
 {% endblock %}

app/modules/dev_tools/templates/dev_tools/admin/testing-dashboard.html

@@ -8,7 +8,7 @@
 {% block alpine_data %}testingDashboard(){% endblock %}
 
 {% block extra_scripts %}
-<script defer src="{{ url_for('dev_tools_static', path='admin/js/testing-dashboard.js') }}"></script>
+<script defer src="{{ static_v(request, 'dev_tools_static', path='admin/js/testing-dashboard.js') }}"></script>
 {% endblock %}
 
 {% block content %}

app/modules/dev_tools/templates/dev_tools/admin/testing-hub.html

@@ -218,5 +218,5 @@
 
 {% block extra_scripts %}
 {# ✅ CRITICAL: Load JavaScript file #}
-<script defer src="{{ url_for('dev_tools_static', path='admin/js/testing-hub.js') }}"></script>
+<script defer src="{{ static_v(request, 'dev_tools_static', path='admin/js/testing-hub.js') }}"></script>
 {% endblock %}

app/modules/dev_tools/templates/dev_tools/admin/translation-editor.html

@@ -159,5 +159,5 @@
 {% endblock %}
 
 {% block extra_scripts %}
-<script defer src="{{ url_for('dev_tools_static', path='admin/js/translation-editor.js') }}"></script>
+<script defer src="{{ static_v(request, 'dev_tools_static', path='admin/js/translation-editor.js') }}"></script>
 {% endblock %}