fix: resolve homepage sections editor and rendering issues

- Fix sections editor not showing by converting isHomepage getter to property
- Add Alpine Collapse plugin for accordion animations
- Fix Quill editor content not syncing after page load
- Add platform dropdown to content page edit form
- Create shared templates config (app/templates_config.py) with i18n globals
  to make _() translation function available in Jinja2 macros
- Fix pricing template field names (monthly_price → price_monthly)
- Fix translation key (pricing.save_20 → pricing.save_months)
- Add tiers context to CMS homepage route for pricing section
- Fix architecture validation issues (language defaults, inline SVGs → $icon)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/templates/platform/sections/_hero.html

@@ -3,8 +3,8 @@
 {#
     Parameters:
     - hero: HeroSection object (or dict)
-    - lang: Current language code (from request.state.language)
-    - default_lang: Fallback language (from platform.default_language)
+    - lang: Current language code (passed from parent template)
+    - default_lang: Fallback language (passed from parent template)
 #}
 
 {% macro render_hero(hero, lang, default_lang) %}