v2.0.0 — Pure glue architecture: zero copied code, pluggable channels

BREAKING: Complete architectural rewrite.

Before: Copied x-reader's fetcher code into readers/ (1205 lines of borrowed code)
After: Pluggable channel system where each channel is a thin wrapper (~50 lines)
       around the best external tool for that platform. Zero copied code.

Architecture:
- channels/base.py — Universal Channel interface (read, search, check)
- channels/web.py — Jina Reader API (swappable)
- channels/github.py — GitHub API (swappable)
- channels/twitter.py — birdx + Jina fallback (swappable)
- channels/youtube.py — yt-dlp (swappable)
- channels/reddit.py — Reddit JSON API + proxy (swappable)
- channels/rss.py — feedparser (swappable)
- channels/bilibili.py — Bilibili API (swappable)
- channels/exa_search.py — Exa semantic search (swappable)

Key design: every backend can be swapped by changing ONE file.
YouTube dies? Change youtube.py. Exa sucks? Swap exa_search.py for Tavily.
Nothing else changes.

Removed: reader.py, schema.py, readers/, search/, utils/ (all x-reader code)
Tests: 36/36 passing

tests/test_core.py

@@ -2,9 +2,6 @@
 """Tests for AgentEyes core class."""
 
 import pytest
-from unittest.mock import patch, MagicMock, AsyncMock
-from pathlib import Path
-
 from agent_eyes.config import Config
 from agent_eyes.core import AgentEyes
 
@@ -18,22 +15,20 @@ def eyes(tmp_path):
 class TestAgentEyes:
     def test_init(self, eyes):
         assert eyes.config is not None
-        assert eyes.reader is not None
 
     def test_detect_platform(self, eyes):
-        assert eyes.detect_platform("https://github.com/openai/gpt-4") == "github"
+        assert eyes.detect_platform("https://github.com/test/repo") == "github"
         assert eyes.detect_platform("https://reddit.com/r/test") == "reddit"
-        assert eyes.detect_platform("https://x.com/elonmusk/status/123") == "twitter"
+        assert eyes.detect_platform("https://x.com/user/status/123") == "twitter"
         assert eyes.detect_platform("https://youtube.com/watch?v=abc") == "youtube"
         assert eyes.detect_platform("https://bilibili.com/video/BV1xx") == "bilibili"
-        assert eyes.detect_platform("https://mp.weixin.qq.com/s/abc") == "wechat"
-        assert eyes.detect_platform("https://example.com") == "generic"
+        assert eyes.detect_platform("https://example.com") == "web"
 
     def test_doctor(self, eyes):
         results = eyes.doctor()
         assert isinstance(results, dict)
         assert "web" in results
-        assert "github_read" in results
+        assert "github" in results
 
     def test_doctor_report(self, eyes):
         report = eyes.doctor_report()