feat(site): implement subdomain discovery and enhanced monitoring dashboard

This commit introduces a comprehensive subdomain discovery system and significantly upgrades the monitoring and domain management user interfaces.

Key changes include:
- **Subdomain Discovery**: Added a new service in the hub that performs advanced subdomain discovery using DNS brute forcing, Certificate Transparency (CT) log searches, pattern enumeration, and HTTP probing.
- **Enhanced Domain Management**:
    - Added API endpoints for retrieving, discovering, and deleting subdomains.
    - Implemented a new `SubdomainList` component in the UI to manage discovered subdomains.
    - Improved WHOIS lookup robustness by supporting a wider range of registry field variations.
- **Advanced Monitoring UI**:
    - Introduced `GroupedMonitorsTable` to organize monitors by root domain and their respective subdomains.
    - Added visual uptime timelines (heartbeat dots) and response time statistics (Avg, Min, Max, P95, P99) to the monitor detail view.
    - Implemented "Uptime Pills" for high-visibility status indicators in the monitors table.
- **Status Page Management**: Replaced the static status pages table with a full `StatusPageManager` capable of managing status pages and incidents.
- **Refactoring & Cleanup**:
    - Cleaned up `.gitignore` and removed unused reference submodules.
    - Improved domain extraction and grouping logic in the frontend.
    - Enhanced the `SystemsTable` with better sorting and layout.

.gitignore

@@ -38,16 +38,15 @@ __debug_*
 *timestamp*
 .playwright-cli/
 
-# Reference code (external projects)
+# Reference code (external projects) - cleaned up
 reference/
 
-# Graphify output - only keep json, md, html in root
-graphify-out/*/
-graphify-out/*.svg
-!graphify-out/*.json
-!graphify-out/*.md
-!graphify-out/*.html
-
 # Environment
 .env
 .env.local
+
+graphify-out/*
+!graphify-out/*.svg
+!graphify-out/*.json
+!graphify-out/*.md
+!graphify-out/*.html