fix(ingestor): align WebSocket subscribe + routing with live API (#105)

* fix(ingestor): align WebSocket subscribe + routing with live API

The Polymarket ws-live-data WebSocket requires `action: "subscribe"` in
the subscribe envelope. Without it the server accepts the connection but
never delivers trade events, causing the tracker to silently produce
zero alerts.

Additionally, incoming frames are shaped `{connection_id, payload:{...}}`
-- they do NOT echo the `topic`/`type` keys we sent. The previous routing
check matched nothing and every real trade was silently dropped.

Changes:
- Add `action: "subscribe"` to subscription message
- Route incoming messages by payload shape (transactionHash + proxyWallet)
- Add ratchet tests for payload routing edge cases
- Rewrite README as agent-first with <2min quickstart
- Add skill draft (docs/skill-tracking-prediction-market-flow.md)

Closes #89

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

* fix(lint): remove unused imports in test_pipeline_persistence

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

* style: apply ruff formatting

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

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_pipeline_persistence.py

@@ -6,14 +6,13 @@ wallet_profiles and funding_transfers tables when fresh wallets are detected.
 
 from __future__ import annotations
 
-import asyncio
 from datetime import UTC, datetime
 from decimal import Decimal
-from unittest.mock import AsyncMock, MagicMock, patch
+from unittest.mock import AsyncMock, MagicMock
 
 import pytest
 from sqlalchemy import select
-from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
+from sqlalchemy.ext.asyncio import async_sessionmaker, create_async_engine
 
 from polymarket_insider_tracker.config import Settings
 from polymarket_insider_tracker.detector.models import FreshWalletSignal
@@ -83,9 +82,7 @@ async def db_manager(async_engine):
     manager._sync_engine = None
     manager._async_engine = async_engine
     manager._sync_session_factory = None
-    manager._async_session_factory = async_sessionmaker(
-        bind=async_engine, expire_on_commit=False
-    )
+    manager._async_session_factory = async_sessionmaker(bind=async_engine, expire_on_commit=False)
     return manager
 
 
@@ -266,9 +263,7 @@ class TestPipelinePersistence:
 
         # Use a broken db_manager that raises on get_async_session
         broken_db = MagicMock()
-        broken_db.get_async_session = MagicMock(
-            side_effect=Exception("DB connection failed")
-        )
+        broken_db.get_async_session = MagicMock(side_effect=Exception("DB connection failed"))
         pipeline._db_manager = broken_db
 
         fresh_signal = FreshWalletSignal(