fix(M1): correction des écarts d'audit FIXME_M1

- requires-python : >=3.13 → >=3.13.5 (alignement sur le contrat TODO.md)
- test de fumée : ajout de tests/unit/test_smoke.py (pytest sort code 0)
- .gitignore : ajout de la règle *.tmp.ics pour les artefacts iCal temporaires
- .secrets.baseline : audit du faux positif GUIDE_DEV_PYTHON.md:5112
  (is_secret: false, is_verified: true → VERIFIED_FALSE)

Co-authored-by: opencode/coder <coder@agents.invalid>
Co-authored-by: opencode/verifier <verifier@agents.invalid>

pyproject.toml

@@ -7,7 +7,7 @@ name = "pronote-sync"
 version = "0.1.0"
 description = "Synchronisation Pronote → CalDAV + XMPP"
 license = {text = "MIT"}
-requires-python = ">=3.13"
+requires-python = ">=3.13.5"
 authors = [
     {name = "Votre Nom", email = "votre@email.com"}
 ]