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/libs/deerflow_api/client.py

@@ -12,10 +12,26 @@ from collections.abc import AsyncGenerator
 
 import httpx
 
+from langbot.pkg.utils import httpclient
+
 from .errors import DeerFlowAPIError
 
 
 SSE_MAX_BUFFER_CHARS = 1_048_576
+SSE_MAX_TOTAL_BYTES = 16 * 1024 * 1024
+ERROR_BODY_MAX_BYTES = 1024 * 1024
+
+
+async def _read_error_body(response: httpx.Response) -> str:
+    body = bytearray()
+    async for chunk in response.aiter_bytes(8192):
+        body.extend(chunk)
+        if len(body) > ERROR_BODY_MAX_BYTES:
+            raise DeerFlowAPIError(
+                operation='read error response',
+                body='response exceeds the runtime limit',
+            )
+    return body.decode('utf-8', errors='replace')
 
 
 def _normalize_sse_newlines(text: str) -> str:
@@ -94,6 +110,7 @@ class AsyncDeerFlowClient:
         async with httpx.AsyncClient(
             trust_env=True,
             timeout=timeout,
+            event_hooks=httpclient.httpx_response_limit_hooks(),
         ) as client:
             response = await client.post(
                 url,
@@ -101,13 +118,14 @@ class AsyncDeerFlowClient:
                 json=payload,
             )
             if response.status_code not in (200, 201):
+                body = await httpclient.response_text(response)
                 raise DeerFlowAPIError(
                     operation='create thread',
                     status=response.status_code,
-                    body=response.text,
+                    body=body,
                     url=url,
                 )
-            return response.json()
+            return await httpclient.parse_json_response(response)
 
     async def delete_thread(self, thread_id: str, timeout: float = 20) -> None:
         """删除指定 thread"""
@@ -116,13 +134,15 @@ class AsyncDeerFlowClient:
         async with httpx.AsyncClient(
             trust_env=True,
             timeout=timeout,
+            event_hooks=httpclient.httpx_response_limit_hooks(),
         ) as client:
             response = await client.delete(url, headers=self.headers)
             if response.status_code not in (200, 202, 204, 404):
+                body = await httpclient.response_text(response)
                 raise DeerFlowAPIError(
                     operation='delete thread',
                     status=response.status_code,
-                    body=response.text,
+                    body=body,
                     url=url,
                     thread_id=thread_id,
                 )
@@ -163,19 +183,27 @@ class AsyncDeerFlowClient:
                 json=payload,
             ) as resp:
                 if resp.status_code != 200:
-                    body = await resp.aread()
                     raise DeerFlowAPIError(
                         operation='runs/stream request',
                         status=resp.status_code,
-                        body=body.decode('utf-8', errors='replace'),
+                        body=await _read_error_body(resp),
                         url=url,
                         thread_id=thread_id,
                     )
 
                 decoder = codecs.getincrementaldecoder('utf-8')('replace')
                 buffer = ''
+                total_bytes = 0
 
                 async for chunk in resp.aiter_bytes(8192):
+                    total_bytes += len(chunk)
+                    if total_bytes > SSE_MAX_TOTAL_BYTES:
+                        raise DeerFlowAPIError(
+                            operation='runs/stream response',
+                            body='response exceeds the runtime limit',
+                            url=url,
+                            thread_id=thread_id,
+                        )
                     buffer += _normalize_sse_newlines(decoder.decode(chunk))
 
                     while '\n\n' in buffer: