feat(v1.2.0): retry API, dernier commit, tri, coloration, export JSON

- client.py: _get_with_retry (max 2 retries, backoff lineaire), get_latest_commit
- collector.py: champ last_commit_date dans RepoData
- display.py: colonne "Dernier commit", _sort_repos (name/issues/release/activity),
  _colorize_milestone_due (rouge/jaune/vert selon echeance)
- cli.py: options --sort/-s et --format/-f (table/json)
- exporter.py: nouveau module, repos_to_dicts + export_json
- 88 tests (35 nouveaux), ruff clean

fixes #8, fixes #7, fixes #10, fixes #9, fixes #6

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

tests/test_display.py

@@ -5,7 +5,9 @@ from io import StringIO
 from rich.console import Console
 
 from gitea_dashboard.collector import RepoData
-from gitea_dashboard.display import render_dashboard
+from gitea_dashboard.display import (
+    render_dashboard,
+)
 
 
 def _make_console():
@@ -28,6 +30,7 @@ def _make_repo(
     is_mirror=False,
     latest_release=None,
     milestones=None,
+    last_commit_date=None,
 ):
     """Build a RepoData for testing."""
     return RepoData(
@@ -40,6 +43,7 @@ def _make_repo(
         is_mirror=is_mirror,
         latest_release=latest_release,
         milestones=milestones if milestones is not None else [],
+        last_commit_date=last_commit_date,
     )
 
 
@@ -142,6 +146,41 @@ class TestRenderDashboardTable:
         assert "repo-beta" in output
 
 
+class TestRenderDashboardLastCommit:
+    """Test the last commit column rendering."""
+
+    def test_last_commit_column_displayed(self):
+        """Column 'Dernier commit' appears in the table."""
+        console, buf = _make_console()
+        repos = [_make_repo(name="projet", last_commit_date="2026-03-10T14:30:00Z")]
+
+        render_dashboard(repos, console=console)
+        output = buf.getvalue()
+
+        assert "Dernier commit" in output
+
+    def test_last_commit_shows_relative_date(self):
+        """Last commit date is shown as relative date."""
+        console, buf = _make_console()
+        repos = [_make_repo(name="projet", last_commit_date="2026-03-10T14:30:00Z")]
+
+        render_dashboard(repos, console=console)
+        output = buf.getvalue()
+
+        # Should show some relative date (il y a Xj, etc.)
+        assert "il y a" in output or "aujourd'hui" in output
+
+    def test_last_commit_none_shows_dash(self):
+        """Repo without commit shows dash."""
+        console, buf = _make_console()
+        repos = [_make_repo(name="vide", last_commit_date=None)]
+
+        render_dashboard(repos, console=console)
+        output = buf.getvalue()
+
+        assert "\u2014" in output or "—" in output
+
+
 class TestRenderDashboardMilestones:
     """Test the milestones section rendering."""
 
@@ -214,3 +253,95 @@ class TestRenderDashboardEmpty:
         output = buf.getvalue()
 
         assert "Aucun repo" in output
+
+
+class TestColorizeMilestoneDue:
+    """Test _colorize_milestone_due function."""
+
+    def test_overdue(self):
+        """Past due date returns 'red'."""
+        from gitea_dashboard.display import _colorize_milestone_due
+
+        assert _colorize_milestone_due("2020-01-01T00:00:00Z") == "red"
+
+    def test_soon(self):
+        """Due date within 7 days returns 'yellow'."""
+        from datetime import datetime, timedelta, timezone
+
+        from gitea_dashboard.display import _colorize_milestone_due
+
+        soon = datetime.now(timezone.utc) + timedelta(days=3)
+        assert _colorize_milestone_due(soon.isoformat()) == "yellow"
+
+    def test_ok(self):
+        """Due date more than 7 days away returns 'green'."""
+        from datetime import datetime, timedelta, timezone
+
+        from gitea_dashboard.display import _colorize_milestone_due
+
+        future = datetime.now(timezone.utc) + timedelta(days=15)
+        assert _colorize_milestone_due(future.isoformat()) == "green"
+
+    def test_no_due(self):
+        """No due date returns empty string."""
+        from gitea_dashboard.display import _colorize_milestone_due
+
+        assert _colorize_milestone_due(None) == ""
+
+
+class TestSortRepos:
+    """Test _sort_repos function."""
+
+    def test_sort_by_name(self):
+        """Sorts alphabetically by name (case-insensitive)."""
+        from gitea_dashboard.display import _sort_repos
+
+        repos = [
+            _make_repo(name="Charlie"),
+            _make_repo(name="alpha"),
+            _make_repo(name="Bravo"),
+        ]
+        result = _sort_repos(repos, "name")
+        assert [r.name for r in result] == ["alpha", "Bravo", "Charlie"]
+
+    def test_sort_by_issues(self):
+        """Sorts by issues count descending."""
+        from gitea_dashboard.display import _sort_repos
+
+        repos = [
+            _make_repo(name="low", open_issues=1),
+            _make_repo(name="high", open_issues=10),
+            _make_repo(name="mid", open_issues=5),
+        ]
+        result = _sort_repos(repos, "issues")
+        assert [r.name for r in result] == ["high", "mid", "low"]
+
+    def test_sort_by_release(self):
+        """Sorts by release date descending; repos without release last."""
+        from gitea_dashboard.display import _sort_repos
+
+        repos = [
+            _make_repo(name="no-rel", latest_release=None),
+            _make_repo(
+                name="old",
+                latest_release={"tag_name": "v1.0", "published_at": "2025-01-01T00:00:00Z"},
+            ),
+            _make_repo(
+                name="new",
+                latest_release={"tag_name": "v2.0", "published_at": "2026-03-01T00:00:00Z"},
+            ),
+        ]
+        result = _sort_repos(repos, "release")
+        assert [r.name for r in result] == ["new", "old", "no-rel"]
+
+    def test_sort_by_activity(self):
+        """Sorts by last commit date descending; repos without commit last."""
+        from gitea_dashboard.display import _sort_repos
+
+        repos = [
+            _make_repo(name="inactive", last_commit_date=None),
+            _make_repo(name="old-commit", last_commit_date="2025-06-01T00:00:00Z"),
+            _make_repo(name="recent", last_commit_date="2026-03-10T00:00:00Z"),
+        ]
+        result = _sort_repos(repos, "activity")
+        assert [r.name for r in result] == ["recent", "old-commit", "inactive"]