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>

conjurer_librarian/search_bot2.py

@@ -108,7 +108,7 @@ def consumer(in_q, control_q, doi, live_results, result_list, control_dict, no,
                 print(f"C{no}{alive_no}\r", end="")
                 for item in result_list:
                     if item["DOI"] in data[0] and not item["exists"]:
-                        print(f"HIT in {no} content {data[0]} line {data[1]} file {data[2]} {item["exists"]}")
+                        print(f"HIT in {no} content {data[0]} line {data[1]} file {data[2]} {item['exists']}")
                         item["exists"] = True
                         live_results.append(item)
                     done_check = done_check and item["exists"]