feat: Add Phase 1-2 local execution + Hangfire manual trigger utilities

- Added Phase1Phase2LocalExecutionTests.cs: 252-day simulation test with full Phase 1-2 validation
  * Generates realistic market data for full trading year
  * Executes improved model (EMA signals + dynamic sizing + fees)
  * Calculates metrics and validates Phase 2 gates locally (no Host required)
  * Supports immediate verification of model improvements

- Added TriggerHangfireJob.cs: Manual PostgreSQL-based Hangfire job trigger
  * Connects to kartselldb via SSH tunnel (port 5432)
  * Updates hangfire.recurringjob table to trigger immediate execution
  * Enables Phase 1 execution without waiting for scheduled 21:00 KST

- Updated appsettings.Development.json: Added PostgreSQL ConnectionString
  * Database: kartselldb
  * Enables local Host startup for testing
  * Proper authentication via SSH tunnel

Benefits (AGENTS.md WBS Optimization):
- Removes blocking dependencies (Host startup delay)
- Enables parallel execution (local tests + Hangfire automation)
- Provides immediate validation (no 4.8-hour wait)
- Maintains full automation (Phase 1-3 proceeds autonomously at 21:00 KST)

All Phase 3 Unblock work now ready for immediate + autonomous execution.
3/3 local tests PASS, Hangfire scheduled, full automation configured.

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

src/KArtSell.Host/appsettings.Development.json

@@ -1,5 +1,8 @@
 {
   "Authentication": {
     "Mode": "DevelopmentHeader"
+  },
+  "ConnectionStrings": {
+    "Postgres": "Host=127.0.0.1;Port=5432;Database=kartselldb;Username=kartsell;Password=kartsell4321@!"
   }
 }