Add deployment infrastructure and development guide

- db/migrations/: V001 (schema) + V002 (seed data) SQL files
- deploy/: systemd service files (taxbaik.service, taxbaik-admin.service)
- deploy/: Nginx location block configuration
- .gitea/workflows/deploy.yml: CI/CD pipeline (build, test, deploy)
- CLAUDE.md: Comprehensive development guidelines (9 sections)

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

db/migrations/V002__SeedData.sql

@@ -0,0 +1,15 @@
+-- V002 - Seed Categories and Settings
+
+INSERT INTO categories (name, slug, sort_order) VALUES
+    ('사업자 세무',   'business-tax',    1),
+    ('부동산 세금',   'real-estate-tax', 2),
+    ('종합소득세',    'income-tax',      3),
+    ('부가가치세',    'vat',             4),
+    ('가족자산·증여', 'family-asset',    5);
+
+INSERT INTO site_settings (key, value) VALUES
+    ('site.title',           '백원숙 세무회계 | 성북구 세무사'),
+    ('site.description',     '사업자 세무, 부동산 양도세·증여세, 종합소득세 상담. 성북구 백원숙 세무사.'),
+    ('kakao.channel.url',    ''),
+    ('phone.main',           ''),
+    ('consultation.fee.text','상담료 7만~20만 원, 계약 체결 시 일부 차감');