ci: replace broken default workflows with compile/unit/integration CI

The two scaffold workflows (Python application / Python package) failed on
every PR: they installed deps from a non-existent requirements.txt, ran
flake8/pytest over the vendored yt_dlp fork (new syntax under the 3.8/3.9
matrix), and collected ad-hoc root scripts — notably test_ai.py, which is
an invalid pasted object dump (not Python).

- Remove python-app.yml / python-package.yml and the junk root scripts
  (test.py, test_ai.py, test_time.py)
- Add .github/workflows/ci.yml with three PR-check jobs:
  * compile     — py_compile every first-party .py (no deps)
  * unit        — pytest on pure logic (conanjurer_functions, constants)
  * integration — boot the Flask services and assert the X-Conjurer-Api-Key
                  auth contract (communication_subroutine + conjurer_musician)
- Add tests/ suite, pytest.ini (testpaths=tests) and conftest.py (sys.path)

Fixes surfaced by the compile gate / needed for the integration job:
- conjurer_librarian/search_bot.py + search_bot2.py: f-string reused the
  same quote ({item["exists"]}) -> SyntaxError on Python < 3.12
- conjurer_musician/media_search_functions.py: made import-safe
  (env-overridable paths, lazy DB load / mkdir) so the service can be
  imported and tested off the Pi

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/integration/test_comm_auth.py

@@ -0,0 +1,56 @@
+"""Integration: the bot's communication Flask layer enforces the shared key,
+and the key the bot would *send* (constants.service_headers) is accepted.
+"""
+import constants
+import communication_subroutine as cs
+
+
+def _client(key="test-secret"):
+    cs.API_KEY = key
+    return cs.app.test_client()
+
+
+def test_prepped_tracks_rejected_without_key():
+    client = _client()
+    resp = client.post(
+        "/prepped_tracks", data='["all", "x"]', content_type="application/json"
+    )
+    assert resp.status_code == 401
+
+
+def test_prepped_tracks_accepted_with_key():
+    client = _client()
+    resp = client.post(
+        "/prepped_tracks",
+        data='["all", "x"]',
+        headers={"X-Conjurer-Api-Key": "test-secret"},
+        content_type="application/json",
+    )
+    assert resp.status_code == 200
+
+
+def test_conjurer_get_is_open():
+    client = _client()
+    assert client.get("/conjurer").status_code == 200
+
+
+def test_open_when_key_unset():
+    client = _client(key=None)
+    resp = client.post(
+        "/prepped_tracks", data='["all", "x"]', content_type="application/json"
+    )
+    assert resp.status_code == 200
+
+
+def test_bot_service_headers_accepted_by_service(monkeypatch):
+    # End-to-end auth contract: the header constants.service_headers() produces
+    # is exactly what communication_subroutine._authorize_request() expects.
+    monkeypatch.setattr(constants, "API_SHARED_KEY", "shared-xyz")
+    cs.API_KEY = "shared-xyz"
+    resp = cs.app.test_client().post(
+        "/prepped_tracks",
+        data='["all", "x"]',
+        headers=constants.service_headers(),
+        content_type="application/json",
+    )
+    assert resp.status_code == 200