fix(server): pin all validated addresses; keep tests out of the build

Addresses the round-2 Copilot review (both suppressed comments).

- createPinnedAgent now takes the whole validated address list instead of
  a single IP, so Node's address-family fallback still works: a
  dual-stack host whose first address is unreachable (IPv6 on an
  IPv4-only network) connects via a later one. The set net.connect may
  choose from is exactly the prevalidated set, so the TOCTOU guarantee is
  unchanged. Empty input throws ProxyTargetError rather than pinning
  undefined.
- Tests: dual-stack pass-through, the empty-list guard, and an
  end-to-end request where the first pinned address is a black hole
  (2001:db8::1) and the connection must complete via the second.
- server/tsconfig.json excludes src/**/__tests__/** so the suite is no
  longer emitted into build/ and published with the package (verified:
  build/__tests__ is gone). tsconfig.test.json keeps the suite
  type-checked, and `npm test` runs it before vitest.

Signed-off-by: cliffhall <cliff@futurescale.com>

server/package.json

@@ -25,7 +25,7 @@
     "start": "node build/index.js",
     "dev": "tsx watch --clear-screen=false src/index.ts",
     "dev:windows": "tsx watch --clear-screen=false src/index.ts < NUL",
-    "test": "vitest run",
+    "test": "tsc -p tsconfig.test.json && vitest run",
     "test:watch": "vitest"
   },
   "devDependencies": {