fix(backend): Fix BUG-001 and BUG-003 - Auto-migration and BCrypt hashes

Fixed two P0 critical bugs blocking Docker development environment:

BUG-001: Database migration not executed automatically
- Added auto-migration code in Program.cs for Development environment
- Migrates Identity, ProjectManagement, and IssueManagement modules
- Prevents app startup if migration fails
- Logs migration progress with clear success/error messages

BUG-003: Seed data password hashes were placeholders
- Generated real BCrypt hashes for Demo@123456 (workFactor=11)
- Updated owner@demo.com and developer@demo.com passwords
- Hash: $2a$11$VkcKFpWpEurtrkrEJzd1lOaDEa/KAXiOZzOUE94mfMFlqBNkANxSK
- Users can now successfully log in with demo credentials

Changes:
- Program.cs: Added auto-migration logic (lines 204-247)
- seed-data.sql: Replaced placeholder hashes with real BCrypt hashes

Testing:
- dotnet build: SUCCESS
- dotnet test: 73/77 tests passing (4 skipped, 4 pre-existing SignalR failures)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

scripts/seed-data.sql

@@ -70,8 +70,8 @@ BEGIN
         v_owner_user_id,
         v_tenant_id,
         'owner@demo.com',
-        -- BCrypt hash for 'Demo@123456'
-        '$2a$11$ZqX5Z5Z5Z5Z5Z5Z5Z5Z5ZuZqX5Z5Z5Z5Z5Z5Z5Z5Z5Z5Z5Z5Z5Z5Z5',
+        -- BCrypt hash for 'Demo@123456' (workFactor=11)
+        '$2a$11$VkcKFpWpEurtrkrEJzd1lOaDEa/KAXiOZzOUE94mfMFlqBNkANxSK',
         'John Owner',
         'Active',
         'local',
@@ -94,8 +94,8 @@ BEGIN
         v_developer_user_id,
         v_tenant_id,
         'developer@demo.com',
-        -- BCrypt hash for 'Demo@123456'
-        '$2a$11$ZqX5Z5Z5Z5Z5Z5Z5Z5Z5ZuZqX5Z5Z5Z5Z5Z5Z5Z5Z5Z5Z5Z5Z5Z5Z5',
+        -- BCrypt hash for 'Demo@123456' (workFactor=11)
+        '$2a$11$VkcKFpWpEurtrkrEJzd1lOaDEa/KAXiOZzOUE94mfMFlqBNkANxSK',
         'Jane Developer',
         'Active',
         'local',