chore(F.4e): remove env-based site loading, unify OAuth Clients, update docs

- Remove env-based site discovery from SiteManager and ProjectManager
- Unify admin and user OAuth Clients into single role-based page
- Update all documentation to reflect DB-based site management
- Clean up env.example, README, ARCHITECTURE docs
- Improve Projects page empty state with link to My Sites
- Remove obsolete env discovery tests

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

env.example

@@ -2,7 +2,7 @@
 # MCP Hub — Environment Configuration
 # ===================================
 #
-# MINIMUM TO START: Just set MASTER_API_KEY and one site below.
+# MINIMUM TO START: Set MASTER_API_KEY, then add sites via the web dashboard.
 # Full docs: https://github.com/airano-ir/mcphub/blob/main/docs/getting-started.md
 #
 # After editing, run:
@@ -49,117 +49,14 @@ DASHBOARD_SESSION_SECRET=
 # DISABLE_MASTER_KEY_LOGIN=false
 
 # ============================================
-# WORDPRESS SITES
+# SITES
 # ============================================
-# Pattern: WORDPRESS_{SITE_ID}_{CONFIG_KEY}
-# Add as many sites as you want (SITE1, SITE2, SITE3, ...)
+# Sites are managed via the web dashboard (DB-based).
+# After starting the server, open the dashboard to add sites:
+#   http://localhost:8000/dashboard
 #
-# How to create a WordPress Application Password:
-#   1. Log into WordPress admin → Users → Your Profile
-#   2. Scroll to "Application Passwords" section
-#   3. Enter name "MCP Hub" → click "Add New"
-#   4. Copy the generated password (format: xxxx xxxx xxxx xxxx)
-
-WORDPRESS_SITE1_URL=https://your-site.com
-WORDPRESS_SITE1_USERNAME=admin
-WORDPRESS_SITE1_APP_PASSWORD=xxxx xxxx xxxx xxxx
-WORDPRESS_SITE1_ALIAS=mysite
-
-# Optional: Docker container name for WP-CLI tools (cache flush, transients, etc.)
-# Find your container name with: docker ps --filter name=wordpress
-# This lets MCP Hub run wp-cli commands inside your WordPress container.
-# WORDPRESS_SITE1_CONTAINER=wordpress-container-name
-
-# Second site example (uncomment to use):
-# WORDPRESS_SITE2_URL=https://another-site.com
-# WORDPRESS_SITE2_USERNAME=admin
-# WORDPRESS_SITE2_APP_PASSWORD=yyyy yyyy yyyy yyyy
-# WORDPRESS_SITE2_ALIAS=blog
-
-# ============================================
-# WORDPRESS ADVANCED (database, bulk, system)
-# ============================================
-# Pattern: WORDPRESS_ADVANCED_{SITE_ID}_{CONFIG_KEY}
-# Provides database operations, bulk operations, and system management.
-# REQUIRES Docker socket AND container name — all tools use WP-CLI.
-#
-# Uses the same credentials as WordPress, but the CONTAINER key is REQUIRED.
-# WORDPRESS_ADVANCED_SITE1_URL=https://your-site.com
-# WORDPRESS_ADVANCED_SITE1_USERNAME=admin
-# WORDPRESS_ADVANCED_SITE1_APP_PASSWORD=xxxx xxxx xxxx xxxx
-# WORDPRESS_ADVANCED_SITE1_CONTAINER=wordpress-container-name
-# WORDPRESS_ADVANCED_SITE1_ALIAS=mysite-advanced
-
-# ============================================
-# WOOCOMMERCE STORES
-# ============================================
-# Pattern: WOOCOMMERCE_{STORE_ID}_{CONFIG_KEY}
-# WooCommerce is a separate plugin — uses Consumer Key/Secret, not App Passwords.
-#
-# Create keys: WooCommerce → Settings → Advanced → REST API → Add Key
-
-# WOOCOMMERCE_STORE1_URL=https://your-store.com
-# WOOCOMMERCE_STORE1_CONSUMER_KEY=ck_xxxxx
-# WOOCOMMERCE_STORE1_CONSUMER_SECRET=cs_xxxxx
-# WOOCOMMERCE_STORE1_ALIAS=mystore
-
-# ============================================
-# OTHER PLUGINS (uncomment to use)
-# ============================================
-# All plugins auto-discover their environment variables at startup.
-# Pattern: {PLUGIN_TYPE}_{INSTANCE_ID}_{CONFIG_KEY}
-
-# --- Gitea ---
-# GITEA_REPO1_URL=https://git.example.com
-# GITEA_REPO1_TOKEN=your_gitea_token
-# GITEA_REPO1_ALIAS=mygitea
-
-# --- n8n ---
-# N8N_INSTANCE1_URL=https://n8n.example.com
-# N8N_INSTANCE1_API_KEY=your_n8n_api_key
-# N8N_INSTANCE1_ALIAS=myn8n
-
-# --- Supabase (Self-Hosted or Cloud) ---
-# Works with both self-hosted Supabase and supabase.com cloud projects.
-# For cloud: URL is https://xxxx.supabase.co
-# For self-hosted: URL is your Kong gateway (e.g., http://your-server:8000)
-#
-# SERVICE_ROLE_KEY is required (bypasses RLS, full admin access).
-# ANON_KEY is optional — if omitted, SERVICE_ROLE_KEY is used for all calls.
-#
-# Note: postgres-meta tools (list_tables, execute_sql, get_table_schema, etc.)
-# require the /pg/ Kong route or a direct META_URL. These tools do NOT work
-# on supabase.com cloud (postgres-meta is internal only on cloud).
-# PostgREST/Auth/Storage/Functions tools work on both cloud and self-hosted.
-#
-# SUPABASE_PROJECT1_URL=https://xxxx.supabase.co
-# SUPABASE_PROJECT1_SERVICE_ROLE_KEY=your_service_role_key
-# SUPABASE_PROJECT1_ANON_KEY=your_anon_key
-# SUPABASE_PROJECT1_ALIAS=mysupabase
-#
-# Optional: direct postgres-meta URL for self-hosted when /pg/ is not via Kong:
-# SUPABASE_PROJECT1_META_URL=http://localhost:5555
-#
-# Optional: Basic Auth for postgres-meta when exposed via a public URL.
-# Format: username:password — not needed for internal Docker networks or Kong.
-# SUPABASE_PROJECT1_META_AUTH=admin:secretpassword
-
-# --- OpenPanel ---
-# OPENPANEL_INSTANCE1_URL=https://openpanel.example.com
-# OPENPANEL_INSTANCE1_CLIENT_ID=your_client_id
-# OPENPANEL_INSTANCE1_CLIENT_SECRET=your_client_secret
-# OPENPANEL_INSTANCE1_ALIAS=myopenpanel
-
-# --- Appwrite ---
-# APPWRITE_PROJECT1_URL=https://appwrite.example.com
-# APPWRITE_PROJECT1_API_KEY=your_appwrite_api_key
-# APPWRITE_PROJECT1_PROJECT_ID=your_project_id
-# APPWRITE_PROJECT1_ALIAS=myappwrite
-
-# --- Directus ---
-# DIRECTUS_INSTANCE1_URL=https://directus.example.com
-# DIRECTUS_INSTANCE1_TOKEN=your_directus_token
-# DIRECTUS_INSTANCE1_ALIAS=mydirectus
+# Supported plugins: WordPress, WooCommerce, Supabase, OpenPanel,
+#   Gitea, n8n, Appwrite, Directus, WordPress Advanced
 
 # ============================================
 # OAUTH (optional — for ChatGPT/Claude auto-registration)