rename: Agent Eyes → Agent Reach

全局重命名：
- 包名: agent_eyes → agent_reach
- CLI: agent-eyes → agent-reach
- 类名: AgentEyes → AgentReach
- 显示名: Agent Eyes → Agent Reach
- GitHub: Panniantong/agent-eyes → Panniantong/Agent-Reach

所有 36 个测试通过，CLI/doctor/read/search 全部正常。

agent_reach/doctor.py

@@ -0,0 +1,77 @@
+# -*- coding: utf-8 -*-
+"""Environment health checker — powered by channels.
+
+Each channel knows how to check itself. Doctor just collects the results.
+"""
+
+from typing import Dict
+from agent_reach.config import Config
+from agent_reach.channels import get_all_channels
+
+
+def check_all(config: Config) -> Dict[str, dict]:
+    """Check all channels and return status dict."""
+    results = {}
+    for ch in get_all_channels():
+        status, message = ch.check(config)
+        results[ch.name] = {
+            "status": status,
+            "name": ch.description,
+            "message": message,
+            "tier": ch.tier,
+            "backends": ch.backends,
+        }
+    return results
+
+
+def format_report(results: Dict[str, dict]) -> str:
+    """Format results as a readable text report."""
+    lines = []
+    lines.append("👁️  Agent Reach 状态")
+    lines.append("=" * 40)
+
+    ok_count = sum(1 for r in results.values() if r["status"] == "ok")
+    total = len(results)
+
+    # Tier 0 — zero config
+    lines.append("")
+    lines.append("✅ 装好即用：")
+    for key, r in results.items():
+        if r["tier"] == 0:
+            if r["status"] == "ok":
+                lines.append(f"  ✅ {r['name']} — {r['message']}")
+            elif r["status"] == "warn":
+                lines.append(f"  ⚠️  {r['name']} — {r['message']}")
+            elif r["status"] in ("off", "error"):
+                lines.append(f"  ❌ {r['name']} — {r['message']}")
+
+    # Tier 1 — needs free key
+    tier1 = {k: r for k, r in results.items() if r["tier"] == 1}
+    if tier1:
+        lines.append("")
+        lines.append("🔍 搜索（免费 Exa Key 即可解锁）：")
+        for key, r in tier1.items():
+            if r["status"] == "ok":
+                lines.append(f"  ✅ {r['name']}")
+            else:
+                lines.append(f"  ⬜ {r['name']} — 注册 exa.ai 获取免费 Key，配置一下就能用")
+
+    # Tier 2 — optional setup
+    tier2 = {k: r for k, r in results.items() if r["tier"] == 2}
+    if tier2:
+        lines.append("")
+        lines.append("🔧 配置后可用：")
+        for key, r in tier2.items():
+            if r["status"] == "ok":
+                lines.append(f"  ✅ {r['name']} — {r['message']}")
+            elif r["status"] == "warn":
+                lines.append(f"  ⚠️  {r['name']} — {r['message']}")
+            else:
+                lines.append(f"  ⬜ {r['name']} — {r['message']}")
+
+    lines.append("")
+    lines.append(f"状态：{ok_count}/{total} 个渠道可用")
+    if ok_count < total:
+        lines.append("运行 `agent-reach setup` 解锁更多渠道")
+
+    return "\n".join(lines)