fix(docmost-seed): handle Docmost data envelope + add format field

Docmost API responses wrap : {data, success, status} (3 keys top-level).
- _post auto-unwrap si payload contient `data` dict|list
- create_page : ajout du field 'format' (markdown|json|html) requis
- welcome_page_content() : retourne markdown plain (Docmost convertit auto en Tiptap)

Iteration 3 BUILD validee en local :
  Workspace : Acadenice (id 019e034d-...)
  3 spaces  : CFA, Agence, Interne
  Page test : Welcome formation-hub dans CFA
  Share URL : http://localhost:3000/share/019e0352-7fc4-7639...

Endpoints reverse-engineered confirmes fonctionnels :
  /api/auth/setup, /api/auth/login, /api/workspace/info,
  /api/spaces/, /api/spaces/create, /api/pages/create, /api/shares/create

docmost/setup/seed.py

@@ -35,12 +35,19 @@ class DocmostSeed:
         self.workspace_id: str | None = None
 
     def _post(self, path: str, body: dict[str, Any] | None = None) -> dict[str, Any]:
+        """POST + auto-unwrap `data` envelope (Docmost API wrap convention)."""
         url = f"{self.base_url}{path}"
         r = self.session.post(url, json=body or {})
         if r.status_code >= 300:
             print(f"    [ERROR] POST {path} → {r.status_code}\n      body={body}\n      resp={r.text[:500]}")
             r.raise_for_status()
-        return r.json() if r.text else {}
+        if not r.text:
+            return {}
+        payload = r.json()
+        # Docmost wraps responses : {data: ..., success: bool, status: int}
+        if isinstance(payload, dict) and "data" in payload and isinstance(payload["data"], (dict, list)):
+            return payload["data"]
+        return payload
 
     def setup_admin_and_workspace(self, name: str, email: str, password: str, workspace_name: str) -> bool:
         """POST /api/auth/setup — bootstrap workspace + admin (1ere fois seulement).
@@ -72,7 +79,12 @@ class DocmostSeed:
     def list_spaces(self) -> list[dict[str, Any]]:
         try:
             data = self._post("/api/spaces/", {"page": 1, "limit": 100})
-            return data.get("items") or data.get("data") or []
+            # Apres unwrap de data, on a { items: [...], meta: {...} }
+            if isinstance(data, dict):
+                return data.get("items") or []
+            if isinstance(data, list):
+                return data
+            return []
         except requests.HTTPError:
             return []
 
@@ -97,8 +109,8 @@ class DocmostSeed:
         print(f"  [space] Created '{name}' id={sid}")
         return sid
 
-    def create_page(self, space_id: str, title: str, content: dict[str, Any] | None = None) -> str:
-        body: dict[str, Any] = {"spaceId": space_id, "title": title}
+    def create_page(self, space_id: str, title: str, content: str | dict[str, Any] | None = None, fmt: str = "markdown") -> str:
+        body: dict[str, Any] = {"spaceId": space_id, "title": title, "format": fmt}
         if content is not None:
             body["content"] = content
         result = self._post("/api/pages/create", body)
@@ -118,34 +130,31 @@ class DocmostSeed:
         return result
 
 
-def welcome_page_content() -> dict[str, Any]:
-    """Tiptap doc JSON minimal pour la page Welcome."""
-    return {
-        "type": "doc",
-        "content": [
-            {"type": "heading", "attrs": {"level": 1}, "content": [
-                {"type": "text", "text": "Welcome formation-hub"}]},
-            {"type": "paragraph", "content": [
-                {"type": "text", "text": "Wiki Docmost interne Acadenice — voir docs/ du repo wiki pour la conception complete."}]},
-            {"type": "heading", "attrs": {"level": 2}, "content": [
-                {"type": "text", "text": "Stack"}]},
-            {"type": "bulletList", "content": [
-                {"type": "listItem", "content": [
-                    {"type": "paragraph", "content": [
-                        {"type": "text", "marks": [{"type": "bold"}], "text": "Docmost"},
-                        {"type": "text", "text": " : ce wiki (AGPL self-host)"}]}]},
-                {"type": "listItem", "content": [
-                    {"type": "paragraph", "content": [
-                        {"type": "text", "marks": [{"type": "bold"}], "text": "Baserow"},
-                        {"type": "text", "text": " : DBs structurees (MIT self-host)"}]}]},
-                {"type": "listItem", "content": [
-                    {"type": "paragraph", "content": [
-                        {"type": "text", "marks": [{"type": "bold"}], "text": "Bridge service"},
-                        {"type": "text", "text": " : Phase 2"}]}]}]},
-            {"type": "paragraph", "content": [
-                {"type": "text", "text": "Note : ajouter les blocks Mermaid / Drawio / Excalidraw via le slash menu une fois la page ouverte (ils ne sont pas pre-inserees par le seed)."}]},
-        ],
-    }
+def welcome_page_content() -> str:
+    """Page Welcome en markdown — Docmost le converti en Tiptap auto."""
+    return """# Welcome formation-hub
+
+Wiki Docmost interne Acadenice — voir `docs/` du repo wiki pour la conception complete.
+
+## Stack
+
+- **Docmost** : ce wiki (AGPL self-host)
+- **Baserow** : DBs structurees (MIT self-host) — http://localhost:8080
+- **Bridge service** : Phase 2
+
+## Diagrammes natifs
+
+Ajouter via le slash menu :
+- `/mermaid` pour les diagrammes Mermaid
+- `/drawio` pour les diagrammes Draw.io
+- `/excalidraw` pour les whiteboards Excalidraw
+
+## Liens utiles
+
+- Repo Forgejo : https://git.acadenice.com/AcadeNice/Wiki
+- Stack locale : Docmost (3000) + Baserow (8080)
+- Documentation projet : `docs/00-readme.md` du repo
+"""
 
 
 def main() -> int: