feat(0.35.0): jalons en écriture depuis la page Projet (issue #26)

- Clients : create_milestone / update_milestone (cache
  invalidé) ; GitHub hérite des mêmes endpoints.
- API Kanbante : création, modification (titre/échéance,
  échéance vidée = retirée), fermeture ; CSRF, validation
  de date avant toute écriture, erreurs forge en 502.
- Page Projet : formulaire 'Nouveau jalon' + édition/
  fermeture par jalon (project.js versionné).
- Échéance à midi UTC : à minuit, le fuseau de l'instance
  Gitea faisait reculer la date affichée d'un jour (réel).
- 291 tests verts (5 nouveaux, palier 24) ; cycle réel
  complet sur Projets/kanbante (jalons smoke #37/#38 créés,
  dates vérifiées, fermés).

tests/conftest.py

@@ -359,15 +359,64 @@ class FakeGitea:
         else:
             self.starred.discard(f"{owner}/{repo}")
 
-    async def get_milestones(self, owner, repo, state="open"):
-        return [
+    @property
+    def _milestones(self):
+        return self.__dict__.setdefault(
+            "milestones_store",
             {
-                "id": 1, "title": "Sprint 1",
-                "due_on": "2026-10-20T00:00:00Z",
-                "open_issues": 1, "closed_issues": 1,
-            }
+                "Projets/demo": [
+                    {
+                        "id": 1, "title": "Sprint 1",
+                        "description": "",
+                        "due_on": "2026-10-20T00:00:00Z",
+                        "state": "open",
+                        "open_issues": 1, "closed_issues": 1,
+                    }
+                ]
+            },
+        )
+
+    async def get_milestones(self, owner, repo, state="open"):
+        items = self._milestones.get(f"{owner}/{repo}", [])
+        return [
+            dict(m) for m in items
+            if state == "all" or m.get("state", "open") == state
         ]
 
+    async def create_milestone(
+        self, owner, repo, title, description="", due_on=None
+    ):
+        store = self._milestones.setdefault(f"{owner}/{repo}", [])
+        milestone = {
+            "id": 100 + len(store),
+            "title": title,
+            "description": description,
+            "due_on": due_on,
+            "state": "open",
+            "open_issues": 0, "closed_issues": 0,
+        }
+        store.append(milestone)
+        return dict(milestone)
+
+    async def update_milestone(
+        self, owner, repo, milestone_id, title=None, description=None,
+        due_on=None, clear_due=False, state=None,
+    ):
+        for m in self._milestones.get(f"{owner}/{repo}", []):
+            if m["id"] == milestone_id:
+                if title is not None:
+                    m["title"] = title
+                if description is not None:
+                    m["description"] = description
+                if clear_due:
+                    m["due_on"] = None
+                elif due_on:
+                    m["due_on"] = due_on
+                if state is not None:
+                    m["state"] = state
+                return dict(m)
+        raise AssertionError("jalon introuvable dans le faux")
+
     async def create_issue(self, owner, repo, title, body=""):
         self._next_number += 1
         issue = _issue(self._next_number, title)

tests/test_palier24.py

@@ -0,0 +1,77 @@
+"""Palier 24 (0.35.0, issue #26): jalons en écriture —
+créer, modifier (titre/échéance), fermer, depuis Kanbante."""
+
+from tests.conftest import csrf_from
+
+
+def test_milestone_create_via_api(client, fake_gitea):
+    token = csrf_from(client)
+    r = client.post(
+        "/api/repos/Projets/demo/milestones",
+        data={
+            "title": "Version 2.0",
+            "description": "Le gros morceau",
+            "due_on": "2027-01-31",
+            "csrf_token": token,
+        },
+    )
+    assert r.status_code == 201
+    payload = r.json()
+    assert payload["ok"] is True
+    assert payload["milestone"]["title"] == "Version 2.0"
+    assert payload["milestone"]["due_on"] == "2027-01-31T12:00:00Z"
+    titles = [
+        m["title"] for m in fake_gitea._milestones["Projets/demo"]
+    ]
+    assert "Version 2.0" in titles
+
+
+def test_milestone_create_rejects_bad_date(client, fake_gitea):
+    token = csrf_from(client)
+    avant = len(fake_gitea._milestones["Projets/demo"])
+    r = client.post(
+        "/api/repos/Projets/demo/milestones",
+        data={
+            "title": "Jalon invalide",
+            "due_on": "31/01/2027",
+            "csrf_token": token,
+        },
+    )
+    assert r.status_code == 400
+    # Rien d'écrit côté forge.
+    assert len(fake_gitea._milestones["Projets/demo"]) == avant
+
+
+def test_milestone_update_title_and_clear_due(client, fake_gitea):
+    token = csrf_from(client)
+    r = client.post(
+        "/api/repos/Projets/demo/milestones/1/update",
+        data={"title": "Sprint 1 — prolongé", "due_on": "", "csrf_token": token},
+    )
+    assert r.status_code == 200
+    sprint = fake_gitea._milestones["Projets/demo"][0]
+    assert sprint["title"] == "Sprint 1 — prolongé"
+    assert sprint["due_on"] is None  # échéance retirée
+
+
+def test_milestone_close(client, fake_gitea):
+    token = csrf_from(client)
+    r = client.post(
+        "/api/repos/Projets/demo/milestones/1/close",
+        data={"csrf_token": token},
+    )
+    assert r.status_code == 200
+    assert fake_gitea._milestones["Projets/demo"][0]["state"] == "closed"
+    # La page Projet ne liste plus le jalon fermé parmi les ouverts.
+    page = client.get("/project/Projets/demo")
+    assert "Version" in page.text  # la page répond toujours
+    assert 'data-action="/api/repos/Projets/demo/milestones"' in page.text
+
+
+def test_project_page_has_milestone_management(client):
+    page = client.get("/project/Projets/demo")
+    assert page.status_code == 200
+    assert "Nouveau jalon" in page.text
+    assert "Modifier / fermer" in page.text
+    assert 'name="due_on"' in page.text
+    assert "/static/js/project.js?v=" in page.text