feat: KIS (Korea Investment) market data collector service

- KIS API integration for stock prices and market data
- GET /stocks endpoint with search, filter, pagination
- GET /stocks/{code} endpoint with prices and valuation
- REST API with health, streams, and trigger endpoints
- Redis Streams for async job processing
- Docker support with multi-stage build

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.dockerignore

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+__pycache__
+*.pyc
+.git
+.venv
+*.egg-info
+dist
+build
+.env