feat(devops): CI/CD + Docker + Monitoring infrastructure

- Multi-stage Dockerfile (builder+runner, <500MB target)
- docker-compose.yml: app(x4) + postgres + redis + prometheus + grafana + nginx
- .env.example with all required secrets (never hardcoded)
- requirements.txt with all dependencies including prometheus-client, alembic
- GitHub Actions CI: lint (flake8+bandit+safety) + tests + Docker build/push
- GitHub Actions CD: staging deploy -> smoke tests -> production deploy + rollback
- Alembic migration setup + initial PostgreSQL schema (001_initial_schema)
- SQLite→PostgreSQL data migration script
- Prometheus metrics module (HTTP, ML, DB, business metrics)
- Prometheus alert rules (5xx >1%, latency >2s, disk >80%, ML accuracy)
- Grafana dashboard (overview: req/s, p95, ML accuracy, error rate)
- Nginx reverse proxy config (HTTPS/TLS, rate limiting, security headers)
- Structured JSON logging module
- Automated daily DB backup script (pg_dump + 30-day retention)

Branch: feature/devops-cicd

Co-Authored-By: Paperclip <noreply@paperclip.ing>

migrations/script.py.mako

@@ -0,0 +1,26 @@
+"""${message}
+
+Revision ID: ${up_revision}
+Revises: ${down_revision | comma,n}
+Create Date: ${create_date}
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+${imports if imports else ""}
+
+# revision identifiers, used by Alembic.
+revision: str = ${repr(up_revision)}
+down_revision: Union[str, None] = ${repr(down_revision)}
+branch_labels: Union[str, Sequence[str], None] = ${repr(branch_labels)}
+depends_on: Union[str, Sequence[str], None] = ${repr(depends_on)}
+
+
+def upgrade() -> None:
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade() -> None:
+    ${downgrades if downgrades else "pass"}