refactor: rebrand decp.info to colibre #57

- Rename project from decp.info to colibre across all codebase
- Update domain from https://decp.info to https://colibre.fr
- Update GitHub repo references to ColinMaudry/colibre
- Rename deployment files: decpinfo-backup.* → colibre-backup.*
- Update project configuration and documentation
- Rename project assets: decp.info.png → colibre.png
- Update environment variables and constants (DOMAIN_NAME, TOKEN_PREFIX, GITHUB_REPO, etc.)
- Update URLs in all pages, tests, and configuration files
- Keep DECP acronym in text (unchanged per requirements)
- Add rebrand note to README.md

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

src/pages/reinitialiser_mot_de_passe.py

@@ -8,7 +8,7 @@ NAME = "Réinitialiser le mot de passe"
 register_page(
     __name__,
     path="/reinitialiser-mot-de-passe",
-    title="Nouveau mot de passe | decp.info",
+    title="Nouveau mot de passe | colibre",
     name=NAME,
     description="Choisir un nouveau mot de passe.",
 )