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>

.gitignore

@@ -8,9 +8,9 @@ build
 .env
 
 # DuckDB runtime artifacts (regenerated from decp_prod.parquet at startup)
-**/decp.duckdb
-**/decp.duckdb.tmp
-**/decp.duckdb.lock
+**/colibre.duckdb
+**/colibre.duckdb.tmp
+**/colibre.duckdb.lock
 **/schema.cache.json
 
 # Runtime databases (never commit)