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/provider/runners/n8nsvapi.py

@@ -12,6 +12,8 @@ from ...core import app
 import langbot_plugin.api.entities.builtin.pipeline.query as pipeline_query
 import langbot_plugin.api.entities.builtin.provider.message as provider_message
 
+_MAX_N8N_RESPONSE_CHARS = 1024 * 1024
+
 
 class N8nAPIError(Exception):
     """N8n API 请求失败"""
@@ -94,6 +96,8 @@ class N8nServiceAPIRunner(runner.RequestRunner):
                 else:
                     chunk_str = str(raw_chunk)
 
+                if len(full_text) + len(chunk_str) > _MAX_N8N_RESPONSE_CHARS:
+                    raise N8nAPIError('n8n response exceeds the runtime limit')
                 full_text += chunk_str
                 buffer += chunk_str
 
@@ -112,7 +116,9 @@ class N8nServiceAPIRunner(runner.RequestRunner):
 
                         if obj.get('type') == 'item' and 'content' in obj:
                             chunk_idx += 1
-                            content = obj['content']
+                            content = str(obj['content'])
+                            if len(full_content) + len(content) > _MAX_N8N_RESPONSE_CHARS:
+                                raise N8nAPIError('n8n response exceeds the runtime limit')
                             full_content += content
                         elif obj.get('type') == 'end':
                             is_final = True
@@ -128,6 +134,8 @@ class N8nServiceAPIRunner(runner.RequestRunner):
                     except json.JSONDecodeError:
                         # buffer 末尾可能是一个不完整的 JSON，等待更多数据
                         break
+            except N8nAPIError:
+                raise
             except Exception as e:
                 # 记录解析失败并继续接收后续 chunk
                 try:
@@ -255,7 +263,12 @@ class N8nServiceAPIRunner(runner.RequestRunner):
                 self.webhook_url, json=payload, headers=headers, auth=auth, timeout=self.timeout
             ) as response:
                 if response.status != 200:
-                    error_text = await response.text()
+                    error_text = (
+                        await httpclient.read_limited(
+                            response,
+                            max_bytes=_MAX_N8N_RESPONSE_CHARS,
+                        )
+                    ).decode('utf-8', errors='replace')
                     self.ap.logger.error(f'n8n webhook call failed: {response.status}, {error_text}')
                     raise Exception(f'n8n webhook call failed: {response.status}, {error_text}')