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/inscription.py

@@ -8,9 +8,9 @@ NAME = "Inscription"
 register_page(
     __name__,
     path="/inscription",
-    title="Inscription | decp.info",
+    title="Inscription | colibre",
     name=NAME,
-    description="Créer un compte decp.info.",
+    description="Créer un compte colibre.",
 )
 
 ERROR_MESSAGES = {