test: add comprehensive coverage for cli, chat, renderer, dirs, install, paths

56 new tests covering previously untested modules:
- test_cli.py: memory write/read/append/list + plugin enable/disable + daemon stubs (via CliRunner)
- test_chat_history.py: ConversationHistory build_for_api, add_*/clear, _trim_to_budget
- test_chat_renderer.py: render_text_response return values, void render_* functions
- test_config_dirs.py: bootstrap idempotency, directory/template/vault/db creation
- test_plugin_install.py: list_bundled_plugins, read_manifest, install_bundled_plugin
- test_utils_paths.py: ensure_dir (nested, idempotent), safe_chmod

Total: 171 → 227 passing tests.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/unit/test_utils_paths.py

@@ -0,0 +1,49 @@
+import os
+
+
+def test_ensure_dir_creates_directory(tmp_path):
+    from pyra.utils.paths import ensure_dir
+    target = tmp_path / "new_dir"
+    result = ensure_dir(target, 0o700)
+    assert target.exists()
+    assert target.is_dir()
+
+
+def test_ensure_dir_returns_path(tmp_path):
+    from pyra.utils.paths import ensure_dir
+    target = tmp_path / "new_dir"
+    result = ensure_dir(target)
+    assert result == target
+
+
+def test_ensure_dir_idempotent(tmp_path):
+    from pyra.utils.paths import ensure_dir
+    target = tmp_path / "existing_dir"
+    ensure_dir(target, 0o700)
+    ensure_dir(target, 0o700)  # should not raise
+    assert target.is_dir()
+
+
+def test_ensure_dir_creates_nested(tmp_path):
+    from pyra.utils.paths import ensure_dir
+    target = tmp_path / "a" / "b" / "c"
+    ensure_dir(target, 0o700)
+    assert target.exists()
+
+
+def test_safe_chmod_sets_permissions(tmp_path):
+    from pyra.utils.paths import safe_chmod
+    f = tmp_path / "test.txt"
+    f.write_text("content")
+    safe_chmod(f, 0o600)
+    if os.name != "nt":
+        assert oct(f.stat().st_mode)[-3:] == "600"
+
+
+def test_safe_chmod_different_modes(tmp_path):
+    from pyra.utils.paths import safe_chmod
+    f = tmp_path / "test.txt"
+    f.write_text("content")
+    safe_chmod(f, 0o644)
+    if os.name != "nt":
+        assert oct(f.stat().st_mode)[-3:] == "644"