fix: restore Python 3.10/3.11 support and report MCP version

- Drop backslash from f-string expression in markdown/html.py
- That syntax needs 3.12+ (PEP 701) and broke import on 3.10/3.11
- Add Python matrix 3.10/3.12/3.14/3.15 to the Gitea testing workflow
- Pass project_version() to MCPServer; serverInfo.version was empty
- Cover the reported version with an in-memory MCP client test
- Swap deprecated click.get_text_stream for sys.stdin.isatty()
- Add explicit encoding to native host shim and manifest writes
- Add explicit encoding to the registry lock file open
- Add explicit encoding to every read_text/write_text call in tests
- Bump version to 0.16.10 in pyproject.toml and extension/manifest.json
- Move .python-version to 3.15 and refresh uv.lock

Extension code is unchanged; only the manifest version string moved.

Verified with 778 tests on 3.10 through 3.15, plus a strict run using -X warn_default_encoding with EncodingWarning and DeprecationWarning as errors.

tests/test_native_host.py

@@ -14,9 +14,9 @@ def _raise_system_exit(code: int):
 def test_cleanup_removes_socket_and_registry_entry(monkeypatch, tmp_path):
   alias = "work"
   socket_path = tmp_path / "work.sock"
-  socket_path.write_text("")
+  socket_path.write_text("", encoding="utf-8")
   registry_path = tmp_path / "registry.json"
-  registry_path.write_text(json.dumps({alias: str(socket_path), "other": str(tmp_path / "other.sock")}))
+  registry_path.write_text(json.dumps({alias: str(socket_path), "other": str(tmp_path / "other.sock")}), encoding="utf-8")
 
   monkeypatch.setattr(native_host, "REGISTRY_PATH", registry_path)
   monkeypatch.setattr(native_host, "_socket_path_for", lambda alias: str(socket_path))
@@ -25,7 +25,7 @@ def test_cleanup_removes_socket_and_registry_entry(monkeypatch, tmp_path):
   native_host._cleanup(alias)
 
   assert not socket_path.exists()
-  assert json.loads(registry_path.read_text()) == {"other": str(tmp_path / "other.sock")}
+  assert json.loads(registry_path.read_text(encoding="utf-8")) == {"other": str(tmp_path / "other.sock")}
 
 def test_stdin_reader_cleans_up_on_eof(monkeypatch):
   cleaned = []
@@ -42,14 +42,14 @@ def test_stdin_reader_cleans_up_on_eof(monkeypatch):
 
 def test_cleanup_windows_skips_socket_unlink(monkeypatch, tmp_path):
   registry_path = tmp_path / "registry.json"
-  registry_path.write_text(json.dumps({"work": r"\\.\pipe\browser-cli-work"}))
+  registry_path.write_text(json.dumps({"work": r"\\.\pipe\browser-cli-work"}), encoding="utf-8")
 
   monkeypatch.setattr(native_host, "REGISTRY_PATH", registry_path)
   monkeypatch.setattr(native_host, "is_windows", lambda: True)
 
   native_host._cleanup("work")
 
-  assert json.loads(registry_path.read_text()) == {}
+  assert json.loads(registry_path.read_text(encoding="utf-8")) == {}
 
 def test_stdin_reader_cleans_up_on_bye(monkeypatch):
   cleaned = []