feat(sharing): group-shared calendars in every member's sidebar, person share picker, hidden profiles

- Backend: co-member group_visible calendars now surface in /local/calendars
  (owned=false, shared_by=owner, read-only, group_shared) and in the normal
  /caldav/events merge (via readable_local_calendar_ids), deduped against
  direct shares / group calendars so nothing appears twice.
- Backend: new User.directory_hidden — a user can hide from sharing/group
  pickers (/users/directory), while admin user management (/users/) still lists
  them. Migration + profile GET/PUT.
- Backend: /groups/{id} members carry shares_calendar so clients can drop
  phantom rows for members who share nothing.
- Frontend: reachable "Teilen" button on owned local calendars; share modal is
  now a checkbox multi-select of users (checked = shared). Hidden-profile toggle
  in Settings → Profile. Group member filter only lists members who actually
  share (phantom fix). Calendars shared with me moved to a dedicated read-only
  "shared with me" section in the manage table.
- Tests: group_visible propagation, no-share absence, dedup, directory_hidden.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/routers/groups_router.py

@@ -176,11 +176,22 @@ def _group_detail(db: Session, group: models.Group, current_user: models.User) -
     member_dicts = []
     for i, m in enumerate(members):
         u = db.query(models.User).filter(models.User.id == m.user_id).first()
+        # Whether this member actually shares a calendar into the group (owns a
+        # calendar designated as their group_visible). Lets clients hide phantom
+        # empty rows for members who share nothing.
+        s = db.query(models.UserSettings).filter(models.UserSettings.user_id == m.user_id).first()
+        shares_calendar = False
+        if s and s.group_visible_calendar_id is not None:
+            shares_calendar = db.query(models.LocalCalendar.id).filter(
+                models.LocalCalendar.id == s.group_visible_calendar_id,
+                models.LocalCalendar.user_id == m.user_id,
+            ).first() is not None
         member_dicts.append({
             "id": m.user_id,
             "display_name": (u.display_name or u.username) if u else None,
             "role": m.role,
             "color": m.color or MEMBER_PALETTE[i % len(MEMBER_PALETTE)],
+            "shares_calendar": shares_calendar,
         })
     gcal_id = _group_calendar_id(db, group.id)
     return {

backend/routers/local_router.py

@@ -167,6 +167,23 @@ def list_calendars(
         d = _cal_dict(cal, owned=False, shared_by=group_name, permission="read_write")
         d["group"] = True
         result.append(d)
+
+    # Calendars co-members share into shared groups (group_visible_calendar_id).
+    # Read-only, shown under the owner's name. Deduped against everything above
+    # so a calendar already shared directly / as a group calendar isn't doubled.
+    for cal in permissions.co_member_group_visible_calendars(db, current_user):
+        if cal.id in seen_ids:
+            continue
+        seen_ids.add(cal.id)
+        owner = db.query(models.User).filter(models.User.id == cal.user_id).first()
+        d = _cal_dict(
+            cal, owned=False,
+            shared_by=(owner.display_name or owner.username) if owner else None,
+            permission="read",
+            request=request,
+        )
+        d["group_shared"] = True
+        result.append(d)
     return result
 
 

backend/routers/profile_router.py

@@ -34,6 +34,7 @@ class ProfileUpdate(BaseModel):
     email: Optional[str] = Field(default=None, max_length=120)
     display_name: Optional[str] = Field(default=None, max_length=80)
     username: Optional[str] = Field(default=None, max_length=50)  # login name (stored lowercase)
+    directory_hidden: Optional[bool] = None  # hide from sharing/group pickers
 
 
 def _strip_controls(s: str) -> str:
@@ -66,6 +67,7 @@ def get_profile(current_user: models.User = Depends(get_current_user)):
         "is_admin": current_user.is_admin,
         "has_avatar": current_user.avatar_filename is not None,
         "totp_enabled": current_user.totp_enabled,
+        "directory_hidden": bool(current_user.directory_hidden),
     }
 
 
@@ -109,11 +111,15 @@ def update_profile(
             if taken:
                 raise HTTPException(400, "Username already taken")
             current_user.username = new_login
+            if data.directory_hidden is not None:
+                current_user.directory_hidden = data.directory_hidden
             db.commit()
             # The JWT 'sub' is the login name — renaming it invalidates the old
             # token, so hand back a fresh one for the client to store.
             result["access_token"] = create_access_token({"sub": new_login})
             return result
+    if data.directory_hidden is not None:
+        current_user.directory_hidden = data.directory_hidden
     db.commit()
     return result
 

backend/routers/users_router.py

@@ -53,7 +53,10 @@ def user_directory(
     """
     users = (
         db.query(models.User)
-        .filter(models.User.id != current_user.id)
+        .filter(
+            models.User.id != current_user.id,
+            models.User.directory_hidden == False,  # noqa: E712 — hidden users opt out of pickers
+        )
         .order_by(models.User.username)
         .all()
     )