feat(cli): add main entry point with error handling (fixes #4)

Read GITEA_TOKEN (required) and GITEA_URL (default) from env vars,
orchestrate client/collect/render pipeline, handle connection and
timeout errors gracefully. Never expose token in error messages.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/gitea_dashboard/cli.py

@@ -1,6 +1,58 @@
-"""Entry point for gitea-dashboard CLI."""
+"""Point d'entree pour le CLI gitea-dashboard."""
+
+from __future__ import annotations
+
+import os
+import sys
+
+import requests
+from rich.console import Console
+
+from gitea_dashboard.client import GiteaClient
+from gitea_dashboard.collector import collect_all
+from gitea_dashboard.display import render_dashboard
+
+_DEFAULT_URL = "http://192.168.0.106:3000"
 
 
-def main():
-    """Run the dashboard."""
-    pass
+def main() -> None:
+    """Point d'entree principal.
+
+    1. Lit GITEA_URL (defaut: http://192.168.0.106:3000) et GITEA_TOKEN (requis)
+    2. Cree le GiteaClient
+    3. Collecte les donnees via collect_all()
+    4. Affiche via render_dashboard()
+    5. Gere les erreurs : config manquante, connexion refusee, timeout
+    """
+    console = Console(stderr=True)
+
+    token = os.environ.get("GITEA_TOKEN")
+    if not token:
+        console.print(
+            "[red]Erreur : GITEA_TOKEN non defini. Exportez la variable d'environnement.[/red]"
+        )
+        sys.exit(1)
+
+    url = os.environ.get("GITEA_URL", _DEFAULT_URL)
+
+    client = GiteaClient(url, token)
+
+    try:
+        repos = collect_all(client)
+    except requests.ConnectionError:
+        console.print("[red]Erreur : connexion refusee. Verifiez l'URL et le serveur Gitea.[/red]")
+        return
+    except requests.Timeout:
+        console.print(
+            "[red]Erreur : delai d'attente depasse. Le serveur Gitea ne repond pas.[/red]"
+        )
+        return
+    except requests.RequestException as exc:
+        # Ne jamais afficher le token dans les messages d'erreur
+        msg = str(exc)
+        if token in msg:
+            msg = msg.replace(token, "***")
+        console.print(f"[red]Erreur API : {msg}[/red]")
+        return
+
+    render_dashboard(repos)