fix(security): critical security fixes (Phase 1)

[saadamjad]

What does this PR do?

Phase 1 of the security audit remediation plan — fixes the CRITICAL and highest-impact HIGH findings that would cause embarrassing failures on day-1 of public launch.

• OTP plaintext logging: no longer logs the OTP code when SMTP is unconfigured in production; raises instead
• CORS wildcard + credentials: allow_origins=["*"] + allow_credentials=True is an invalid combination browsers silently reject. Origins now come from CORS_ORIGINS env var
• User enumeration: POST /v1/auth/request-otp returned 409 for existing emails and 404 for unknown ones. Both cases now return an identical 200 response
• No restart policies: added restart: unless-stopped to every Docker Compose service
• Services bound to 0.0.0.0: Postgres, Qdrant, Redis ports now bind to 127.0.0.1 only
• Shallow health check in deploy script: infra/deploy-production.sh now polls /health/deep (real dependency check) instead of /health (always 200)
• NEXT_PUBLIC_DEV_MODE footgun: deploy script now refuses to deploy if this is still true (bypasses dashboard OTP login)
• Dockerfile ran as root: added non-root USER + core/.dockerignore
• client_ip() spoofing: X-Forwarded-For is now only trusted from a configured trusted proxy address, closing a rate-limit bypass
• Dev API key footgun: refuses to boot if DEV_API_KEY is set while ENV=production; removed the compose default that could silently re-enable the bypass
• Added CHANGELOG.md and .github/PULL_REQUEST_TEMPLATE.md

How to test

# Lint
/Users/apple/Library/Python/3.14/bin/ruff check core/ sdk/python/ mcp/ integrations/

# Core unit tests (includes updated OTP-enumeration and rate-limit tests)
pytest core/tests/ -m "not integration" -v

# SDK + MCP + TS SDK
pytest sdk/python/tests/ -v
pytest mcp/tests/ -v
cd sdk/typescript && npm test

# Dashboard
cd dashboard && npm run lint && npm run build

Manual checks:

• curl -s -o /dev/null -w "%{http_code}" -X POST http://localhost:8000/v1/auth/request-otp -H "Content-Type: application/json" -d '{"email":"nobody@example.com"}' → 200
• Set ENV=production + DEV_API_KEY=zizkadb_dev_local → app refuses to start

Checklist

• Tests pass (pytest core/tests/ -m "not integration" -v — 136 passed)
• Lint passes (ruff check core/ sdk/python/ mcp/ integrations/)
• Dashboard lints clean (npm run lint)
• No new allow_origins=["*"] + allow_credentials=True combinations
• Schema changes are idempotent — N/A, no schema changes in this PR
• Auth dependency is correct — no auth-dependency routing changed
• CHANGELOG.md updated under [Unreleased]

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