Add REST API

[nemoralis]

This PR adds a REST API.

Changes

• Extracted data loading logic from app.py into a new data_store.py module. This allows the database state to be shared between the main Flask app and the new API blueprint without circular imports.
• Created a new api blueprint in api.py with the following endpoints:
  • GET /api/events: List all available events.
  • GET /api/events/<slug>: Get detailed statistics for a specific event (e.g., monuments2016).
  • GET /api/country/<name>: Get statistics for a specific country.

[sourcery-ai]

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[JeanFred]

Thanks a lot for this! I finally had time to look at it.

• I could test this fine with the docker-compose setup and the dummy database − all 3 endpoints answer as expected
• Formatter/Linter is unfortunately broken in this repo :-( but I did have a pass locally. I also broke out your commit in two and copied over your excellent explanations from the PR. I would have liked to push them (as your kindly ticked "Maintainers are allowed to edit this pull request." alas I could not push the changes [1] (it’s my first time trying to amend someone else's PR from a fork, maybe I did something wrong) − I stashed them in https://github.com/JeanFred/wikiloves/tree/nemoralis/master
• Thanks for making unit tests! I tried running them, both with tox/nose (that setup is a bit broken too >_>) and with uv/pytest − it fails with [2] I think the issue is that the import app, which itself tries loading the DB, is executed before the mock in setUp ?

[1] Getting

! [remote rejected] nemoralis/master -> nemoralis/master (permission denied)
error: failed to push some refs to 'github.com:nemoralis/wikiloves.git'

[2]

======================================================================
ERROR: Failure: JSONDecodeError (Expecting value: line 1 column 1 (char 0))
----------------------------------------------------------------------
Traceback (most recent call last):
  File "wikiloves/.tox/py39/lib/python3.9/site-packages/nose/failure.py", line 39, in runTest
    raise self.exc_val.with_traceback(self.tb)
  File "wikiloves/.tox/py39/lib/python3.9/site-packages/nose/loader.py", line 417, in loadTestsFromName
    module = self.importer.importFromPath(
  File "wikiloves/.tox/py39/lib/python3.9/site-packages/nose/importer.py", line 47, in importFromPath
    return self.importFromDir(dir_path, fqname)
  File "wikiloves/.tox/py39/lib/python3.9/site-packages/nose/importer.py", line 94, in importFromDir
    mod = load_module(part_fqname, fh, filename, desc)
  File ".local/share/uv/python/cpython-3.9.21-linux-x86_64-gnu/lib/python3.9/imp.py", line 234, in load_module
    return load_source(name, filename, file)
  File ".local/share/uv/python/cpython-3.9.21-linux-x86_64-gnu/lib/python3.9/imp.py", line 171, in load_source
    module = _load(spec)
  File "<frozen importlib._bootstrap>", line 711, in _load
  File "<frozen importlib._bootstrap>", line 680, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 850, in exec_module
  File "<frozen importlib._bootstrap>", line 228, in _call_with_frames_removed
  File "wikiloves/tests/test_api.py", line 12, in <module>
    from app import app
  File "wikiloves/app.py", line 29, in <module>
    data_store.loadDB()
  File "wikiloves/data_store.py", line 33, in loadDB
    db = json.load(f)
  File ".local/share/uv/python/cpython-3.9.21-linux-x86_64-gnu/lib/python3.9/json/__init__.py", line 293, in load
    return loads(fp.read(),
  File ".local/share/uv/python/cpython-3.9.21-linux-x86_64-gnu/lib/python3.9/json/__init__.py", line 346, in loads
    return _default_decoder.decode(s)
  File ".local/share/uv/python/cpython-3.9.21-linux-x86_64-gnu/lib/python3.9/json/decoder.py", line 337, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File ".local/share/uv/python/cpython-3.9.21-linux-x86_64-gnu/lib/python3.9/json/decoder.py", line 355, in raw_decode
    raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

[nemoralis]

Thanks for the feedback, I've fixed the test code.