feat(tenancy): add merchant team CRUD with multi-store hub view

The merchant team page was read-only. Now merchant owners can invite,
edit roles, and remove team members across all their stores from a
single hub view.

Architecture: No new models — delegates to existing store_team_service.
Members are deduplicated across stores with per-store role badges.

New:
- 5 API endpoints: GET team (member-centric), GET store roles, POST
  invite (multi-store), PUT update role, DELETE remove member
- merchant-team.js Alpine component with invite/edit/remove modals
- Full CRUD template with stats cards, store filter, member table
- 7 Pydantic schemas for merchant team request/response
- 2 service methods: validate_store_ownership, get_merchant_team_members
- 25 new i18n keys across 4 tenancy locales + 1 core common key

Tests: 434 tenancy tests passing, arch-check green.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/modules/tenancy/schemas/__init__.py

@@ -118,6 +118,12 @@ from app.modules.tenancy.schemas.team import (
     InvitationAccept,
     InvitationAcceptResponse,
     InvitationResponse,
+    MerchantTeamInvite,
+    MerchantTeamInviteResponse,
+    MerchantTeamMemberResponse,
+    MerchantTeamMemberStoreInfo,
+    MerchantTeamOverviewResponse,
+    MerchantTeamStoreInfo,
     PermissionCheckRequest,
     PermissionCheckResponse,
     RoleBase,

app/modules/tenancy/schemas/team.py

@@ -315,3 +315,89 @@ class TeamErrorResponse(BaseModel):
     error_code: str
     message: str
     details: dict | None = None
+
+
+# ============================================================================
+# Merchant Team Schemas (Hub View)
+# ============================================================================
+
+
+class MerchantTeamMemberStoreInfo(BaseModel):
+    """A member's role/status in one specific store."""
+
+    store_id: int
+    store_name: str
+    store_code: str
+    role_name: str | None = None
+    role_id: int | None = None
+    is_active: bool = True
+    is_pending: bool = False
+
+
+class MerchantTeamMemberResponse(BaseModel):
+    """A team member aggregated across all merchant stores."""
+
+    user_id: int
+    email: EmailStr
+    first_name: str | None = None
+    last_name: str | None = None
+    full_name: str
+    stores: list[MerchantTeamMemberStoreInfo] = Field(default_factory=list)
+    is_owner: bool = False
+
+
+class MerchantTeamStoreInfo(BaseModel):
+    """Compact store info for the merchant team overview."""
+
+    id: int
+    name: str
+    code: str
+
+
+class MerchantTeamOverviewResponse(BaseModel):
+    """Merchant team overview with member-centric view."""
+
+    merchant_name: str
+    stores: list[MerchantTeamStoreInfo]
+    members: list[MerchantTeamMemberResponse]
+    total_members: int
+    total_active: int
+    total_pending: int
+
+
+class MerchantTeamInvite(BaseModel):
+    """Schema for inviting a member to merchant stores."""
+
+    email: EmailStr
+    first_name: str | None = Field(None, max_length=100)
+    last_name: str | None = Field(None, max_length=100)
+    store_ids: list[int] = Field(..., min_length=1, description="Store IDs to invite to")
+    role_name: str = Field("staff", description="Role name for all selected stores")
+
+    @field_validator("role_name")
+    @classmethod
+    def validate_role_name(cls, v):
+        """Validate role name is in allowed presets."""
+        allowed_roles = ["manager", "staff", "support", "viewer", "marketing"]
+        if v.lower() not in allowed_roles:
+            raise ValueError(
+                f"Role name must be one of: {', '.join(allowed_roles)}"
+            )
+        return v.lower()
+
+
+class MerchantTeamInviteResult(BaseModel):
+    """Per-store invite result."""
+
+    store_id: int
+    store_name: str
+    success: bool
+    error: str | None = None
+
+
+class MerchantTeamInviteResponse(BaseModel):
+    """Response for merchant team invite (multi-store)."""
+
+    message: str
+    email: EmailStr
+    results: list[MerchantTeamInviteResult]