refactor: DRY pass on backend — pagination helper and sharing utilities

- Add parse_pagination() to routes/utils.py; replace 6 duplicate limit/offset extractions in notes, tasks, chat, projects, milestones routes
- Extract _enrich_shares() in sharing.py; eliminates identical 12-line loop in list_project_shares and list_note_shares
- Extract _deduplicate_by_permission() in sharing.py; eliminates identical deduplication blocks in list_shared_with_me for projects and notes

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

src/fabledassistant/services/sharing.py

@@ -16,6 +16,33 @@ logger = logging.getLogger(__name__)
 VALID_PERMISSIONS = {"viewer", "editor", "admin"}
 
 
+async def _enrich_shares(session, shares) -> list[dict]:
+    """Attach username / group_name to a list of share rows (ProjectShare or NoteShare)."""
+    result = []
+    for s in shares:
+        d = s.to_dict()
+        if s.shared_with_user_id:
+            user = await session.get(User, s.shared_with_user_id)
+            d["username"] = user.username if user else None
+        if s.shared_with_group_id:
+            group = await session.get(Group, s.shared_with_group_id)
+            d["group_name"] = group.name if group else None
+        result.append(d)
+    return result
+
+
+def _deduplicate_by_permission(shares, id_attr: str) -> dict[int, str]:
+    """Return {resource_id: best_permission} keeping the highest-ranked permission per resource."""
+    from fabledassistant.services.access import PERMISSION_RANK
+    seen: dict[int, str] = {}
+    for share in shares:
+        rid = getattr(share, id_attr)
+        prev = seen.get(rid)
+        if prev is None or PERMISSION_RANK[share.permission] > PERMISSION_RANK[prev]:
+            seen[rid] = share.permission
+    return seen
+
+
 # ---------------------------------------------------------------------------
 # Project shares
 # ---------------------------------------------------------------------------
@@ -83,17 +110,7 @@ async def list_project_shares(project_id: int) -> list[dict]:
         shares = (await session.execute(
             select(ProjectShare).where(ProjectShare.project_id == project_id)
         )).scalars().all()
-        result = []
-        for s in shares:
-            d = s.to_dict()
-            if s.shared_with_user_id:
-                user = await session.get(User, s.shared_with_user_id)
-                d["username"] = user.username if user else None
-            if s.shared_with_group_id:
-                group = await session.get(Group, s.shared_with_group_id)
-                d["group_name"] = group.name if group else None
-            result.append(d)
-        return result
+        return await _enrich_shares(session, shares)
 
 
 # ---------------------------------------------------------------------------
@@ -166,17 +183,7 @@ async def list_note_shares(note_id: int) -> list[dict]:
         shares = (await session.execute(
             select(NoteShare).where(NoteShare.note_id == note_id)
         )).scalars().all()
-        result = []
-        for s in shares:
-            d = s.to_dict()
-            if s.shared_with_user_id:
-                user = await session.get(User, s.shared_with_user_id)
-                d["username"] = user.username if user else None
-            if s.shared_with_group_id:
-                group = await session.get(Group, s.shared_with_group_id)
-                d["group_name"] = group.name if group else None
-            result.append(d)
-        return result
+        return await _enrich_shares(session, shares)
 
 
 # ---------------------------------------------------------------------------
@@ -203,12 +210,7 @@ async def list_shared_with_me(user_id: int) -> dict:
                 )
             )).scalars().all()
 
-        seen_projects: dict[int, str] = {}
-        for share in list(proj_direct) + list(proj_group):
-            prev = seen_projects.get(share.project_id)
-            from fabledassistant.services.access import PERMISSION_RANK
-            if prev is None or PERMISSION_RANK[share.permission] > PERMISSION_RANK[prev]:
-                seen_projects[share.project_id] = share.permission
+        seen_projects = _deduplicate_by_permission(list(proj_direct) + list(proj_group), "project_id")
 
         projects = []
         for pid, perm in seen_projects.items():
@@ -239,12 +241,7 @@ async def list_shared_with_me(user_id: int) -> dict:
                 )
             )).scalars().all()
 
-        seen_notes: dict[int, str] = {}
-        for share in list(note_direct) + list(note_group):
-            prev = seen_notes.get(share.note_id)
-            from fabledassistant.services.access import PERMISSION_RANK
-            if prev is None or PERMISSION_RANK[share.permission] > PERMISSION_RANK[prev]:
-                seen_notes[share.note_id] = share.permission
+        seen_notes = _deduplicate_by_permission(list(note_direct) + list(note_group), "note_id")
 
         notes = []
         for nid, perm in seen_notes.items():