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>

.secrets.baseline

@@ -139,7 +139,8 @@
         "type": "Hex High Entropy String",
         "filename": "GUIDE_DEV_PYTHON.md",
         "hashed_secret": "90bd1b48e958257948487b90bee080ba5ed00caa",
-        "is_verified": false,
+        "is_secret": false,
+        "is_verified": true,
         "line_number": 5112
       }
     ]