refactor(tests+frontend): one http_sink helper for the hook tests; apiErrorMessage replaces ten hand-rolled error-body parses; type X, import specifiers are not definitions (#2904, milestone 299 step 6)

tests/helpers.http_sink replaces three module-local _Sink handlers (the
write-path tests and the after-write test). ProjectView + SettingsView
parsed `(e as {body?:{error?}}).body?.error || fallback` by hand ten times
beside the apiErrorMessage canon (#2853) - all ten now call it. The
extractor (server + the hook awk mirror) no longer reads `import { type Foo }`
as a definition of Foo - that was the last "identical body" sym family.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/test_after_write_hook.py

@@ -6,17 +6,16 @@ the pre-write hook's end-to-end tests. Skips where the hook's tools are
 missing; asserts on content where they are present."""
 from __future__ import annotations
 
-import http.server
 import json
 import os
 import shutil
 import subprocess
-import threading
-import urllib.parse
 from pathlib import Path
 
 import pytest
 
+from tests.helpers import http_sink
+
 PLUGIN = Path(__file__).resolve().parents[1] / "plugin"
 HOOK = PLUGIN / "hooks" / "scribe_after_write.sh"
 
@@ -53,66 +52,43 @@ def _run(repo, env, session="s-after-1", tool="Bash"):
     return out.stdout
 
 
-class _Sink(http.server.BaseHTTPRequestHandler):
-    seen: list[dict] = []
-    reply = b'{"context":"> family named","note_ids":[],"sync_note_ids":[],"derive_keys":["dup:483a"]}'
-
-    def do_GET(self):
-        type(self).seen.append(urllib.parse.parse_qs(urllib.parse.urlparse(self.path).query))
-        self.send_response(200)
-        self.send_header("Content-Type", "application/json")
-        self.end_headers()
-        self.wfile.write(type(self).reply)
-
-    def log_message(self, *a):
-        pass
+SINK_REPLY = b'{"context":"> family named","note_ids":[],"sync_note_ids":[],"derive_keys":["dup:483a"]}'
 
 
-@pytest.fixture
-def sink():
-    _Sink.seen = []
-    server = http.server.HTTPServer(("127.0.0.1", 0), _Sink)
-    threading.Thread(target=server.serve_forever, daemon=True).start()
-    try:
-        yield server
-    finally:
-        server.shutdown()
+def test_after_write_names_what_bash_just_wrote_then_stays_quiet_until_the_next_change(tmp_path):
+    with http_sink(SINK_REPLY) as (port, seen):
+        env = _env(tmp_path, url=f"http://127.0.0.1:{port}")
+        repo = _repo(tmp_path, env)
+        # "A Bash call" wrote an untracked stylesheet and appended to a tracked file.
+        (repo / "a.css").write_text(".log-empty {\n  color: red;\n}\n")
+        (repo / "b.py").write_text("def one():\n    return 1\n\ndef slug(t):\n    return t\n")
+        out = _run(repo, env)
+        by_path = {q["path"][0]: q for q in seen}
+        assert set(by_path) == {"a.css", "b.py"}           # repo-relative, like the pre hook
+        assert by_path["a.css"]["shapes"] == ["css:log-empty"]
+        assert by_path["b.py"]["shapes"] == ["sym:slug"]
+        # Added lines only for the tracked file — the existing def is not "just written".
+        assert "def slug" in by_path["b.py"]["code"][0] and "def one" not in by_path["b.py"]["code"][0]
+        ctx = json.loads(out)["hookSpecificOutput"]
+        assert ctx["hookEventName"] == "PostToolUse"
+        assert "> family named" in ctx["additionalContext"]
+        # The local by-name arm rides along: `slug` already lives in c.py.
+        assert "`slug` is already defined in 1 other file(s): c.py" in ctx["additionalContext"]
+        # Derive keys landed on the SHARED channel the pre-write hook reads.
+        state = tmp_path / "scribe-priorart" / "s-after-1.derive.ids"
+        assert "dup:483a" in state.read_text().split()
 
+        # Nothing changed → one git status, no request, no output.
+        seen.clear()
+        assert _run(repo, env) == ""
+        assert seen == []
 
-def test_after_write_names_what_bash_just_wrote_then_stays_quiet_until_the_next_change(tmp_path, sink):
-    env = _env(tmp_path, url=f"http://127.0.0.1:{sink.server_port}")
-    repo = _repo(tmp_path, env)
-    # "A Bash call" wrote an untracked stylesheet and appended to a tracked file.
-    (repo / "a.css").write_text(".log-empty {\n  color: red;\n}\n")
-    (repo / "b.py").write_text("def one():\n    return 1\n\ndef slug(t):\n    return t\n")
-    out = _run(repo, env)
-    by_path = {q["path"][0]: q for q in _Sink.seen}
-    assert set(by_path) == {"a.css", "b.py"}           # repo-relative, like the pre hook
-    assert by_path["a.css"]["shapes"] == ["css:log-empty"]
-    assert by_path["b.py"]["shapes"] == ["sym:slug"]
-    # Added lines only for the tracked file — the existing def is not "just written".
-    assert "def slug" in by_path["b.py"]["code"][0] and "def one" not in by_path["b.py"]["code"][0]
-    ctx = json.loads(out)["hookSpecificOutput"]
-    assert ctx["hookEventName"] == "PostToolUse"
-    assert "> family named" in ctx["additionalContext"]
-    # The local by-name arm rides along: `slug` already lives in c.py.
-    assert "`slug` is already defined in 1 other file(s): c.py" in ctx["additionalContext"]
-    # Derive keys landed on the SHARED channel the pre-write hook reads.
-    state = tmp_path / "scribe-priorart" / "s-after-1.derive.ids"
-    assert "dup:483a" in state.read_text().split()
-
-    # Nothing changed → one git status, no request, no output.
-    _Sink.seen = []
-    assert _run(repo, env) == ""
-    assert _Sink.seen == []
-
-    # Another change → only that file, and the dedup channel goes back up.
-    (repo / "a.css").write_text(".log-empty {\n  color: red;\n}\n.other {\n  margin: 0;\n}\n")
-    _run(repo, env)
-    assert [q["path"][0] for q in _Sink.seen] == ["a.css"]
-    assert _Sink.seen[0]["exclude_derive"] == ["dup:483a"]
-    assert set(_Sink.seen[0]["shapes"][0].split(",")) == {"css:log-empty", "css:other"}
-
+        # Another change → only that file, and the dedup channel goes back up.
+        (repo / "a.css").write_text(".log-empty {\n  color: red;\n}\n.other {\n  margin: 0;\n}\n")
+        _run(repo, env)
+        assert [q["path"][0] for q in seen] == ["a.css"]
+        assert seen[0]["exclude_derive"] == ["dup:483a"]
+        assert set(seen[0]["shapes"][0].split(",")) == {"css:log-empty", "css:other"}
 
 def test_after_write_is_silent_where_it_has_nothing_to_say(tmp_path):
     env = _env(tmp_path)