feat(collector): add RepoData dataclass and collect_all (fixes #2)

- RepoData dataclass with all repo fields
- collect_all enriches each repo with release and milestones
- Computes open_issues = open_issues_count - open_pr_counter
- 6 unit tests with mocked GiteaClient

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

src/gitea_dashboard/collector.py

@@ -0,0 +1,52 @@
+"""Collecte et agregation des donnees repos Gitea."""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+
+from gitea_dashboard.client import GiteaClient
+
+
+@dataclass
+class RepoData:
+    """Donnees agregees d'un repo."""
+
+    name: str
+    full_name: str
+    description: str
+    open_issues: int  # open_issues_count - open_pr_counter
+    is_fork: bool
+    is_archived: bool
+    is_mirror: bool
+    latest_release: dict | None  # {tag_name, published_at} ou None
+    milestones: list[dict]  # [{title, open_issues, closed_issues, due_on}]
+
+
+def collect_all(client: GiteaClient) -> list[RepoData]:
+    """Collecte les donnees de tous les repos.
+
+    Pour chaque repo : enrichit avec release et milestones.
+    Calcule open_issues = open_issues_count - open_pr_counter.
+    """
+    repos = client.get_repos()
+    result: list[RepoData] = []
+
+    for repo in repos:
+        owner = repo["owner"]["login"]
+        name = repo["name"]
+
+        result.append(
+            RepoData(
+                name=name,
+                full_name=repo["full_name"],
+                description=repo.get("description", "") or "",
+                open_issues=repo["open_issues_count"] - repo["open_pr_counter"],
+                is_fork=repo["fork"],
+                is_archived=repo["archived"],
+                is_mirror=repo["mirror"],
+                latest_release=client.get_latest_release(owner, name),
+                milestones=client.get_milestones(owner, name),
+            )
+        )
+
+    return result