feat(tenancy): add Workspace multi-tenant foundation (#2353)

* Document multi-tenant workspace architecture

* Add OSS and commercial workspace boundaries

* docs: redesign multi-tenant workspace architecture

* feat(tenancy): implement workspace isolation

* docs(tenancy): record verification evidence

* docs(tenancy): revise single-instance SaaS topology

* docs(tenancy): refine architecture options

* docs: finalize cloud v2 multi-tenant decisions

* feat(tenancy): establish cloud isolation foundations

* feat(tenancy): harden shared cloud runtime boundaries

* docs(tenancy): record final isolation verification

* fix(tenancy): close isolation and permission gaps

* docs(tenancy): record final isolation verification

* feat(tenancy): connect cloud workspace control plane

* fix(build): install git for pinned SDK

* docs(cloud): update control plane verification

* chore: update multi-tenant SDK pin

* fix(cloud): skip legacy model sync during startup

* test(cloud): preserve minimal model manager fixtures

* fix(cloud): preserve authenticated account context

* fix(cloud): reuse authenticated account for user info

* feat(cloud): complete Workspace settings navigation

* test(web): cover Workspace dropdown menu

* feat(web): place workspace controls in sidebar

* refactor(web): streamline workspace controls

* style(web): format workspace layout test

* fix(cloud): surface runtime and workspace plan status

* fix(plugin): keep runtime identity stable across restarts

* fix(ui): widen and center workspace switcher

* fix(ui): hide roles from workspace switcher

* fix(ui): align workspace switcher with sidebar entries

* feat(workspace): add in-product collaboration and direct Cloud launch

* style: format collaboration changes

* fix(workspace): bind collaboration APIs to tenant UoW

* fix(cloud): preserve Core-owned collaboration state

* test(cloud): require Space identity for invite registration

* feat(cloud): complete secure invitation experience

* style(web): format invitation flows

* fix(cloud): recover box runtime without unscoped skill reload

* feat(oss): enforce invitation account and owner billing flows

* style: format OSS account service

* test(oss): cover invitation logout handoff

* fix(oss): resolve workspace owner in scoped session

* feat(cloud): harden multi-tenant runtime resources

* fix(cloud): bound runtime restart storms

* fix(cloud): eliminate periodic runtime CPU spikes

* fix(cloud): enforce instance capacity ceilings

* fix(cloud): scope public login capability discovery

* fix(cloud): bound tenant maintenance and monitoring work

* fix(runtime): bound tenant resource amplification

* fix(deps): pin green multi-tenant plugin SDK

* fix(cloud): handle unavailable skill capability

* fix(security): require authentication for image file endpoint (H-2)

- Changed /api/v1/files/image from AuthType.NONE to USER_TOKEN_OR_API_KEY
- Added Permission.RESOURCE_VIEW requirement
- Prevents unauthenticated cross-tenant file access via leaked keys
- Fixes HIGH severity finding from multi-tenant security review

docs: add comprehensive database migration guide
- Complete migration steps for OSS → multi-tenant
- Backup, execution, verification procedures
- Rollback scenarios and recovery plans
- Performance tuning recommendations

* test: add comprehensive cross-tenant isolation tests

Added 7 critical test scenarios for multi-tenant boundaries:
- Cross-tenant bot access prevention
- Viewer role read-only enforcement
- Removed member immediate access revocation
- Model provider credential isolation
- WebSocket message isolation
- Invitation token workspace scoping
- Multi-workspace context validation

These tests address P0-2 coverage gaps for:
- workspaces.py (membership & invitation flows)
- user.py (authentication & authorization)
- websocket_chat.py (real-time isolation)
- plugins.py (resource access control)

docs: finalize database migration guide

* fix(security): resolve M-1, M-2, M-3 security findings

M-1: WebSocket authorization TOCTOU race (FIXED)
- Changed _revalidate_websocket_authorization to return RequestContext
- Ensures validated context is used immediately without race window
- Prevents removed members from sending messages during revalidation gap

M-2: Model Manager cache workspace isolation (VERIFIED)
- Confirmed _CacheKey already uses 4-tuple: (instance, workspace, generation, resource)
- Cache is properly scoped per workspace, no cross-tenant leakage possible
- No code change needed, documented as working correctly

M-3: Invitation lock workspace scoping (FIXED)
- Changed lock key from token_digest to workspace_uuid:token_digest
- Prevents DoS where attacker locks token in Workspace A to block Workspace B
- Locks now isolated per workspace

All MEDIUM severity findings from security review now resolved.

* fix(cloud): unblock tenant CI and enforce knowledge quotas

* fix(tenancy): scope rerank model sync

---------

Co-authored-by: dadachann <185672915+dadachann@users.noreply.github.com>

src/langbot/pkg/api/mcp/mount.py

@@ -19,7 +19,10 @@ from __future__ import annotations
 
 import contextlib
 import typing
+import uuid
 
+from ..http.context import PrincipalContext, PrincipalType, RequestContext, WorkspaceContext
+from .context import bind_request_context, reset_request_context
 from .server import LangBotMCPServer
 
 if typing.TYPE_CHECKING:
@@ -28,6 +31,9 @@ if typing.TYPE_CHECKING:
 
 # JSON-RPC-ish 401 body returned before the MCP app is reached.
 _UNAUTHORIZED_BODY = b'{"error":"unauthorized","message":"A valid LangBot API key is required for MCP access."}'
+_ENTITLEMENT_UNAVAILABLE_BODY = (
+    b'{"error":"entitlement_unavailable","message":"Workspace entitlement is unavailable for MCP access."}'
+)
 
 
 def _extract_api_key(headers: list[tuple[bytes, bytes]]) -> str:
@@ -76,7 +82,7 @@ class MCPMount:
     def wrap(self, quart_asgi: typing.Callable) -> typing.Callable:
         """Return a dispatcher ASGI app fronting ``quart_asgi``."""
         mcp_asgi = self._mcp_asgi
-        verify_api_key = self.ap.apikey_service.verify_api_key
+        authenticate_api_key = self.ap.apikey_service.authenticate_api_key
         is_mcp_path = self._is_mcp_path
 
         async def dispatcher(scope, receive, send):  # type: ignore[no-untyped-def]
@@ -88,12 +94,12 @@ class MCPMount:
 
             # Authenticate MCP HTTP requests with a LangBot API key.
             api_key = _extract_api_key(scope.get('headers', []))
-            authorized = False
+            identity = None
             if api_key:
                 with contextlib.suppress(Exception):
-                    authorized = await verify_api_key(api_key)
+                    identity = await authenticate_api_key(api_key)
 
-            if not authorized:
+            if identity is None:
                 await send(
                     {
                         'type': 'http.response.start',
@@ -107,6 +113,56 @@ class MCPMount:
                 await send({'type': 'http.response.body', 'body': _UNAUTHORIZED_BODY})
                 return
 
-            await mcp_asgi(scope, receive, send)
+            deployment_admission = getattr(self.ap, 'deployment_admission', None)
+            try:
+                if deployment_admission is not None:
+                    deployment_admission.require_active()
+                entitlement_revision = 0
+                deployment = getattr(self.ap, 'deployment', None)
+                if deployment is not None and getattr(deployment, 'multi_workspace_enabled', False):
+                    resolver = getattr(self.ap, 'entitlement_resolver', None)
+                    if resolver is None or identity.instance_uuid != resolver.instance_uuid:
+                        raise RuntimeError('Workspace entitlement resolver is unavailable')
+                    entitlement = await resolver.resolve(identity.workspace_uuid)
+                    entitlement_revision = entitlement.entitlement_revision
+            except Exception:
+                await send(
+                    {
+                        'type': 'http.response.start',
+                        'status': 403,
+                        'headers': [(b'content-type', b'application/json')],
+                    }
+                )
+                await send({'type': 'http.response.body', 'body': _ENTITLEMENT_UNAVAILABLE_BODY})
+                return
+
+            request_context = RequestContext(
+                instance_uuid=identity.instance_uuid,
+                placement_generation=identity.placement_generation,
+                request_id=str(uuid.uuid4()),
+                auth_type='api-key',
+                principal=PrincipalContext(
+                    principal_type=PrincipalType.API_KEY,
+                    api_key_uuid=identity.api_key_uuid,
+                ),
+                workspace=WorkspaceContext(
+                    workspace_uuid=identity.workspace_uuid,
+                    membership_uuid=None,
+                    role=None,
+                    permissions=identity.permissions,
+                ),
+                entitlement_revision=entitlement_revision,
+            )
+            tenant_scope = getattr(self.ap.persistence_mgr, 'tenant_scope', None)
+            if not callable(tenant_scope):
+                raise RuntimeError('MCP request persistence scope is unavailable')
+            async with tenant_scope(identity.workspace_uuid):
+                token = bind_request_context(request_context)
+                try:
+                    await mcp_asgi(scope, receive, send)
+                    if deployment_admission is not None:
+                        deployment_admission.require_active()
+                finally:
+                    reset_request_context(token)
 
         return dispatcher