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/http/controller/main.py

@@ -2,6 +2,7 @@ from __future__ import annotations
 
 import asyncio
 import os
+import typing
 
 import quart
 import quart_cors
@@ -27,6 +28,37 @@ importutil.import_modules_in_pkg(groups_knowledge)
 importutil.import_modules_in_pkg(groups_resources)
 
 
+class BoundedJSONRequest(quart.Request):
+    """Parse bounded HTTP JSON bodies outside the shared event loop."""
+
+    async def get_json(
+        self,
+        force: bool = False,
+        silent: bool = False,
+        cache: bool = True,
+    ) -> typing.Any:
+        # Keep Quart's cache and error semantics, changing only where the
+        # potentially 10 MiB JSON decoder runs. The RouterGroup establishes a
+        # trusted Workspace blocking-work scope before calling route handlers.
+        if cache and self._cached_json[silent] is not Ellipsis:
+            return self._cached_json[silent]
+        if not (force or self.is_json):
+            return None
+
+        data = await self.get_data(cache=cache, as_text=False)
+        try:
+            result = await asyncio.to_thread(self.json_module.loads, data)
+        except ValueError as error:
+            if silent:
+                result = None
+            else:
+                result = self.on_json_loading_failed(error)
+
+        if cache:
+            self._cached_json[silent] = result
+        return result
+
+
 class HTTPController:
     ap: app.Application
 
@@ -35,6 +67,7 @@ class HTTPController:
     def __init__(self, ap: app.Application) -> None:
         self.ap = ap
         self.quart_app = quart.Quart(__name__)
+        self.quart_app.request_class = BoundedJSONRequest
         quart_cors.cors(self.quart_app, allow_origin='*')
 
         # Set maximum content length to prevent large file uploads
@@ -103,6 +136,7 @@ class HTTPController:
         config.accesslog = '-'
         config.bind = [f'{host}:{port}']
         config.errorlog = config.accesslog
+        config.websocket_max_message_size = group.MAX_FILE_SIZE
 
         asgi_app = self.quart_app
         if self.mcp_mount is not None:
@@ -113,7 +147,16 @@ class HTTPController:
     async def register_routes(self) -> None:
         @self.quart_app.route('/healthz')
         async def healthz():
-            return {'code': 0, 'msg': 'ok'}
+            get_resource_stats = getattr(
+                self.ap,
+                'get_runtime_resource_stats',
+                None,
+            )
+            return {
+                'code': 0,
+                'msg': 'ok',
+                'resources': (get_resource_stats() if callable(get_resource_stats) else {}),
+            }
 
         for g in group.preregistered_groups:
             ginst = g(self.ap, self.quart_app)