Major overhaul: Collections, DaisyUI, permissions, preview, Phoenix 1.8

Collections Architecture:
- Replace Template Types with Collections (managed/template modes)
- Collection picker when creating new pages
- Collection manager and global collections admin pages
- Migration V003 renames permission scope types

Groups & Permissions:
- Owner account replaces super_admin role
- Site-scoped groups with feature/sub-feature/resource permissions
- Global group templates copied to new sites
- Feature registry with 15 features and sub-features
- Migration V002 creates permissions tables

UI Framework:
- Replace StationUI with DaisyUI
- Use TailwindCompiler NIF with plugin_css API (no npm tailwind)
- Align core components with Phoenix 1.8.5 patterns
- All forms use .form component, all links use navigate/patch

Preview System:
- Draft preview via isolated iframe
- Published preview link
- Preview endpoint renders page with layout and site CSS

Navigation:
- LiveView patch navigation for sidebar (no disconnects)
- Graceful mount fallback for stale session URLs
- Fixed lookup_page to ignore host/port mismatches

Updated deps: Phoenix 1.8.5, LiveView 1.1.28, Bandit 1.10.4

Author: bcardarella

assets/css/beacon_live_admin.css

@@ -1,5 +1,3 @@
-@import "./station-ui.css";
-@import "./station-ui-fonts.css";
 @import "tailwindcss/base";
 @import "tailwindcss/components";
 @import "tailwindcss/utilities";

assets/css/station-ui-fonts.css

@@ -23,6 +23,7 @@
   "devDependencies": {
     "@tailwindcss/container-queries": "^0.1",
     "@tailwindcss/forms": "^0.5.11",
+    "daisyui": "^4.12.24",
     "esbuild": "^0.25",
     "esbuild-plugin-import-glob": "^0.1",
     "esbuild-svelte": "^0.9",