refactor: drop toast + over-engineered extras, add inline admin feedback

Phase 1 cleanup of the personal-site revamp. Backend/architecture untouched;
changes are limited to removing unused complexity and restoring feedback.

Removals
- Toast system: delete react-hot-toast, Toaster, QueryToastBridge, lib/toast,
  the toggle/easter-egg calls, related i18n keys and the dependency.
- Contact protection: remove Turnstile + per-IP rate limiting
  (lib/contact-guard, lib/contact-protection, admin screen, form widget,
  app-config wiring, nav entry, test).
- Speculative specs: delete orders, products, downloads, project-inquiry.

Inline feedback (replaces toast, no new deps)
- Add lib/admin-feedback (withFlash/readFlash) and components/admin/admin-flash,
  rendered centrally by AdminDashboardShell.
- Emit success/error messages for media, site-settings, portfolio, smtp,
  marquee and maintenance actions; pages read them via searchParams.
- Contact form shows validation/delivery errors inline; success still
  redirects to /success.

Docs
- Fix stale paths in frontend-system-* (components/root -> components/admin,
  lib/root-navigation -> lib/admin-navigation, drop phantom src/) and remove
  contact-protection references from docs and CLAUDE.md.
- Add docs/PHASE0_DIAGNOSIS.md (diagnosis report).

Note: proxy.ts self-fetch kept intentionally; it also drives maintenance mode.

docs/frontend-system-audit.md

@@ -140,7 +140,7 @@ Patterns:
 Repeated in:
 
 - `components/dashboard/dashboard-layout.tsx`
-- `components/root/root-dashboard-shell.tsx`
+- `components/admin/root-dashboard-shell.tsx`
 - many `app/root/*/page.tsx`
 
 Patterns:
@@ -160,8 +160,8 @@ Patterns:
 
 Repeated in:
 
-- `components/root/site-settings-form.tsx`
-- `components/root/portfolio-project-form.tsx`
+- `components/admin/site-settings-form.tsx`
+- `components/admin/portfolio-project-form.tsx`
 - `app/root/page.tsx`
 
 Patterns:
@@ -204,7 +204,7 @@ Most repeated token usage:
   - `components/ui/textarea.tsx`
   - `components/ui/select.tsx`
   - `components/dashboard/sidebar.tsx`
-  - `components/root/contact-protection-form.tsx`
+  - `components/admin/contact-protection-form.tsx`
 - `rounded-[var(--radius-pill)]`
   - `components/layout/site-header.tsx`
   - `components/layout/floating-preferences.tsx`
@@ -220,13 +220,13 @@ Most repeated token usage:
   - several content blocks and previews
   - examples:
     - `app/root/page.tsx`
-    - `components/root/site-settings-form.tsx`
-    - `components/root/media-field-picker.tsx`
+    - `components/admin/site-settings-form.tsx`
+    - `components/admin/media-field-picker.tsx`
 - `rounded-lg`
   - examples:
     - `components/ui/dialog.tsx`
     - `components/dashboard/dashboard-layout.tsx`
-    - `components/root/portfolio-project-form.tsx`
+    - `components/admin/portfolio-project-form.tsx`
 
 ## 6. Repeated spacing patterns found in code
 
@@ -321,14 +321,14 @@ Very common combinations:
 - `border border-input bg-background`
   - `components/ui/input.tsx`
   - `components/ui/select.tsx`
-  - `components/root/portfolio-categories-manager.tsx`
-  - `components/root/portfolio-projects-overview.tsx`
+  - `components/admin/portfolio-categories-manager.tsx`
+  - `components/admin/portfolio-projects-overview.tsx`
 - `bg-primary text-primary-foreground`
   - active nav and badges/buttons:
     - `components/ui/button.tsx`
     - `components/ui/badge.tsx`
     - `components/dashboard/sidebar.tsx`
-    - `components/root/portfolio-subnav.tsx`
+    - `components/admin/portfolio-subnav.tsx`
     - `app/[locale]/(site)/portfolio/page.tsx`
 - `text-muted-foreground`
   - repeated throughout forms, cards, table headers, descriptions
@@ -406,7 +406,7 @@ Evidence:
 - dependency in `package.json`
 - broad usage across app and components
 - examples:
-  - `components/root/root-dashboard-shell.tsx`
+  - `components/admin/root-dashboard-shell.tsx`
   - `components/layout/site-header.tsx`
   - `components/theme-toggle.tsx`
   - `app/root/page.tsx`
@@ -422,8 +422,8 @@ No second React icon library is present in `package.json`.
 - public site routes live under:
   - `app/[locale]/(site)/*`
 - admin routes live under:
-  - `app/root/*`
-- `src` exists but is empty in the current codebase.
+  - `app/_admin/*` (canonical source), mirrored to `app/admin-internal/*` (rewrite target) and `app/root/*` (dev alias)
+- there is no `src/` directory in the codebase.
 
 ### Component folders
 
@@ -431,7 +431,7 @@ No second React icon library is present in `package.json`.
   - primitive and near-primitive reusable controls
 - `components/layout`
   - site shell, hero, header, footer, container, backdrops
-- `components/root`
+- `components/admin`
   - admin feature components and forms
 - `components/dashboard`
   - admin navigation and dashboard layout shell
@@ -442,7 +442,7 @@ No second React icon library is present in `package.json`.
 
 - `lib/utils.ts`
   - `cn()`
-- `lib/root-navigation.ts`
+- `lib/admin-navigation.ts`
   - navigation config for admin shell
 - other `lib/*`
   - app settings, metadata, locale, media, portfolio, auth
@@ -457,7 +457,7 @@ Confirmed custom wrappers around local primitive layer:
   - wraps `Button`
 - `components/layout/locale-toggle.tsx`
   - uses `Button` and `DropdownMenu`
-- `components/root/form-save-button.tsx`
+- `components/admin/form-save-button.tsx`
   - uses `Button`
 
 ## 11. Violations or inconsistencies found in the current codebase
@@ -498,8 +498,8 @@ Examples:
 
 - `components/ui/dialog.tsx`
 - `components/dashboard/dashboard-layout.tsx`
-- `components/root/site-settings-form.tsx`
-- `components/root/portfolio-project-form.tsx`
+- `components/admin/site-settings-form.tsx`
+- `components/admin/portfolio-project-form.tsx`
 
 ### Some primitives follow the local system, some keep stock shadcn-style values
 
@@ -529,7 +529,7 @@ So the file defines multiple levels, but two of them are currently identical.
 
 Most interactive primitives use Radix wrappers, but `components/ui/tabs.tsx` is a custom React context implementation instead.
 
-### Tailwind scans `src`, but `src` is empty
+### Tailwind scans `src`, but `src` does not exist
 
 `tailwind.config.ts`
 includes:
@@ -538,7 +538,7 @@ includes:
 
 Current project state:
 
-- `src` contains no files.
+- there is no `src/` directory; this glob matches nothing.
 
 ## 12. Codex rules derived from the existing system