Web search for pi through an existing Chrome over CDP

Attaches to a browser that is already running — never launches one —
using the same endpoint configuration as pi-browser-harness, so a single
/browser-target choice governs both packages.

One tool, castle_cdp_search, deliberately not named web_search so it
coexists with pi-web-access rather than shadowing it.

Notes from validating against castle's Chrome:

- tbs=qdr:*, the parameter Google's own Tools menu writes, renders an
  empty page on this profile; the older as_qdr=* works. Any date filter
  combined with udm=14 is also empty, so recency drops udm.
- Target.createTarget must not be raced against the abort signal:
  raceAbort abandons the promise but cannot cancel the command, and the
  command's side effect is a tab nothing is left holding.
- A search cancelled while queued has to be removed from the semaphore
  queue, or the slot handed to it later is never counted back.
- A decaying rate-limit block stops serving /sorry/ and returns an empty
  results page instead, indistinguishable from a genuine zero-hit search.

1 files changed, 35 insertions, 0 deletions

diff --git a/test/search-url.test.ts b/test/search-url.test.ts
new file mode 100644
index 0000000..13f58d1
--- /dev/null
+++ b/test/search-url.test.ts
@@ -0,0 +1,35 @@
+import assert from "node:assert/strict";
+import { test } from "node:test";
+
+import { buildSearchUrl } from "../src/search.ts";
+
+const paramsOf = (url: string): URLSearchParams => new URL(url).searchParams;
+
+test("a plain query asks for the Web tab in English", () => {
+  const url = buildSearchUrl({ query: "typebox json schema", numResults: 10 });
+  assert.equal(new URL(url).origin + new URL(url).pathname, "https://www.google.com/search");
+  const p = paramsOf(url);
+  assert.equal(p.get("q"), "typebox json schema");
+  assert.equal(p.get("num"), "10");
+  assert.equal(p.get("hl"), "en");
+  assert.equal(p.get("udm"), "14");
+  assert.equal(p.get("tbs"), null);
+});
+
+test("recency uses as_qdr and drops udm — tbs and udm both render an empty page", () => {
+  const cases = { day: "d", week: "w", month: "m", year: "y" } as const;
+  for (const [recency, expected] of Object.entries(cases)) {
+    const url = buildSearchUrl({ query: "q", numResults: 5, recency: recency as keyof typeof cases });
+    const p = paramsOf(url);
+    assert.equal(p.get("as_qdr"), expected, recency);
+    assert.equal(p.get("tbs"), null, `${recency}: tbs must not be used`);
+    assert.equal(p.get("udm"), null, `${recency}: udm must be dropped alongside a date filter`);
+  }
+});
+
+test("queries with characters that would break a URL are encoded", () => {
+  const query = 'site:example.com "exact phrase" a&b?c=d #frag +plus/slash';
+  const url = buildSearchUrl({ query, numResults: 3 });
+  assert.equal(paramsOf(url).get("q"), query);
+  assert.ok(!url.includes(" "), "no raw spaces in the URL");
+});