feat(registry): resolve_by_slug 路径模式解析 + TENANT_SLUG_RE 常量上提

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

tests/test_registry.py

@@ -9,6 +9,7 @@ Windows 纪律:每个建过 engine 的用例结尾 await reg.dispose_all()——
 连接不关,文件锁着,tmp_path 清理 PermissionError。
 """
 import asyncio
+import dataclasses
 import json
 import shutil
 from pathlib import Path
@@ -22,6 +23,7 @@ from app.platform.registry import (
     UnknownTenantError,
     make_tenant_engine,
 )
+from app.platform.tenant_source import FileTenantSource
 
 REPO_ROOT = Path(__file__).resolve().parents[1]
 SEED_DIR = REPO_ROOT / "seed_profiles"
@@ -296,3 +298,45 @@ async def test_reload_to_disabled_releases_engine(tmp_path):
     with pytest.raises(TenantDisabledError):
         await reg.resolve("a.example.com")
     await reg.dispose_all()
+
+
+# ---- 路径前缀模式解析(spec 2026-10-19 §5) ----------------------------------
+
+
+class TestResolveBySlug:
+    """resolve_by_slug:/t/<slug>/ 路径模式的 slug 直查——语义与 resolve_site
+    同款(未知/停用/懒建/reload 竞态取 _ensure_ready 返回值),首站点为默认。"""
+
+    async def test_已知_slug_返回租户与首站点(self, tmp_path):
+        reg = TenantRegistry.load_from_dir(SEED_DIR, data_dir=tmp_path)
+        rt, site = await reg.resolve_by_slug("jiancai")
+        assert rt.config.slug == "jiancai"
+        assert site.slug == rt.config.sites[0].slug  # 首站点为默认
+        await reg.dispose_all()
+
+    async def test_未知_slug_UnknownTenantError(self, tmp_path):
+        reg = TenantRegistry.load_from_dir(SEED_DIR, data_dir=tmp_path)
+        with pytest.raises(UnknownTenantError):
+            await reg.resolve_by_slug("no-such")
+        await reg.dispose_all()
+
+    async def test_停用租户_TenantDisabledError(self, tmp_path):
+        seed = _write_seed(
+            tmp_path, {"jiancai": _tenant("jiancai", status="disabled")})
+        reg = TenantRegistry.load_from_dir(seed, data_dir=tmp_path / "data")
+        with pytest.raises(TenantDisabledError):
+            await reg.resolve_by_slug("jiancai")
+        await reg.dispose_all()
+
+    async def test_空站点表按未知处理(self, tmp_path):
+        """防御分支(spec §5):两源加载期均拒零站点,直装 sites=[] 的
+        LoadedTenant 绕过源校验覆盖该分支——正常运行不可达,防将来源
+        语义漂移。"""
+        seed = _write_seed(tmp_path, {"jiancai": _tenant("jiancai")})
+        source = FileTenantSource(seed)
+        lt = dataclasses.replace(source.read_tenant("jiancai"), sites=[])
+        reg = TenantRegistry(source, data_dir=tmp_path / "data")
+        reg._install([lt])                        # 手工装配(单元测试:直装内部)
+        with pytest.raises(UnknownTenantError):
+            await reg.resolve_by_slug("jiancai")
+        await reg.dispose_all()