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>

tests/unit_tests/test_skill_service.py

@@ -1,11 +1,28 @@
+import io
 from types import SimpleNamespace
 from unittest.mock import AsyncMock
+import zipfile
 
+import httpx
 import pytest
 
+from langbot.pkg.api.http.context import ExecutionContext
 from langbot.pkg.api.http.service.skill import SkillService
 
 
+_CONTEXT = ExecutionContext(
+    instance_uuid='instance-a',
+    workspace_uuid='workspace-a',
+    placement_generation=1,
+)
+
+
+def _workspace_service():
+    return SimpleNamespace(
+        get_execution_binding=AsyncMock(return_value=SimpleNamespace(instance_uuid=_CONTEXT.instance_uuid))
+    )
+
+
 class TestRequireBoxForWrite:
     """Box is the only source of truth for skills — there is no local
     filesystem fallback. Every write and (most) read methods refuse cleanly
@@ -14,6 +31,7 @@ class TestRequireBoxForWrite:
     def _ap_with_disabled_box(self):
         return SimpleNamespace(
             skill_mgr=SimpleNamespace(reload_skills=AsyncMock()),
+            workspace_service=_workspace_service(),
             box_service=SimpleNamespace(
                 available=False,
                 enabled=False,
@@ -24,6 +42,7 @@ class TestRequireBoxForWrite:
     def _ap_with_failed_box(self):
         return SimpleNamespace(
             skill_mgr=SimpleNamespace(reload_skills=AsyncMock()),
+            workspace_service=_workspace_service(),
             box_service=SimpleNamespace(
                 available=False,
                 enabled=True,
@@ -35,55 +54,116 @@ class TestRequireBoxForWrite:
     async def test_create_skill_refused_when_box_disabled(self):
         service = SkillService(self._ap_with_disabled_box())
         with pytest.raises(ValueError, match='disabled in config'):
-            await service.create_skill({'name': 'x'})
+            await service.create_skill(_CONTEXT, {'name': 'x'})
 
     @pytest.mark.asyncio
     async def test_create_skill_refused_when_box_failed(self):
         service = SkillService(self._ap_with_failed_box())
         with pytest.raises(ValueError, match='docker daemon not running'):
-            await service.create_skill({'name': 'x'})
+            await service.create_skill(_CONTEXT, {'name': 'x'})
 
     @pytest.mark.asyncio
     async def test_update_skill_refused_when_box_disabled(self):
         service = SkillService(self._ap_with_disabled_box())
         with pytest.raises(ValueError, match='Editing a skill requires the Box runtime'):
-            await service.update_skill('x', {})
+            await service.update_skill(_CONTEXT, 'x', {})
 
     @pytest.mark.asyncio
     async def test_write_skill_file_refused_when_box_disabled(self):
         service = SkillService(self._ap_with_disabled_box())
         with pytest.raises(ValueError, match='Editing skill files requires the Box runtime'):
-            await service.write_skill_file('x', 'a.txt', 'hi')
+            await service.write_skill_file(_CONTEXT, 'x', 'a.txt', 'hi')
 
     @pytest.mark.asyncio
     async def test_install_from_github_refused_when_box_disabled(self):
         service = SkillService(self._ap_with_disabled_box())
         with pytest.raises(ValueError, match='Installing a skill from GitHub'):
-            await service.install_from_github({'owner': 'o', 'repo': 'r', 'asset_url': 'https://example/x.zip'})
+            await service.install_from_github(
+                _CONTEXT,
+                {'owner': 'o', 'repo': 'r', 'asset_url': 'https://example/x.zip'},
+            )
 
     @pytest.mark.asyncio
     async def test_install_from_zip_upload_refused_when_box_disabled(self):
         service = SkillService(self._ap_with_disabled_box())
         with pytest.raises(ValueError, match='Installing a skill from upload'):
-            await service.install_from_zip_upload(file_bytes=b'', filename='x.zip')
+            await service.install_from_zip_upload(
+                _CONTEXT,
+                file_bytes=b'',
+                filename='x.zip',
+            )
 
     @pytest.mark.asyncio
     async def test_create_skill_refused_when_box_service_missing_entirely(self):
         """No ap.box_service attribute at all (truly minimal setup):
         Box is the only source of truth, so creation must still refuse."""
-        service = SkillService(SimpleNamespace(skill_mgr=SimpleNamespace(reload_skills=AsyncMock())))
+        service = SkillService(
+            SimpleNamespace(
+                skill_mgr=SimpleNamespace(reload_skills=AsyncMock()),
+                workspace_service=_workspace_service(),
+            )
+        )
         with pytest.raises(ValueError, match='not initialised'):
-            await service.create_skill({'name': 'x'})
+            await service.create_skill(_CONTEXT, {'name': 'x'})
 
     @pytest.mark.asyncio
     async def test_list_skills_returns_empty_when_box_unavailable(self):
         """list_skills should render an empty surface (not crash) so the
         skills page can show a banner instead of a broken state."""
         service = SkillService(self._ap_with_disabled_box())
-        assert await service.list_skills() == []
+        assert await service.list_skills(_CONTEXT) == []
 
     @pytest.mark.asyncio
     async def test_read_skill_file_refused_when_box_unavailable(self):
         service = SkillService(self._ap_with_disabled_box())
         with pytest.raises(ValueError, match='Reading a skill file'):
-            await service.read_skill_file('x', 'a.txt')
+            await service.read_skill_file(_CONTEXT, 'x', 'a.txt')
+
+
+class TestGithubSkillArchiveLimits:
+    @staticmethod
+    def _service() -> SkillService:
+        return SkillService(SimpleNamespace())
+
+    @pytest.mark.asyncio
+    async def test_download_rejects_declared_oversized_archive(self, monkeypatch):
+        import langbot.pkg.api.http.service.skill as skill_module
+
+        real_client = httpx.AsyncClient
+
+        def handler(request: httpx.Request) -> httpx.Response:
+            return httpx.Response(
+                200,
+                headers={'content-length': str(10 * 1024 * 1024 + 1)},
+                content=b'',
+                request=request,
+            )
+
+        monkeypatch.setattr(
+            skill_module.httpx,
+            'AsyncClient',
+            lambda **_kwargs: real_client(transport=httpx.MockTransport(handler)),
+        )
+
+        with pytest.raises(ValueError, match='compressed size limit'):
+            await self._service()._download_github_asset('https://codeload.github.com/o/r/zip/main')
+
+    def test_copy_rejects_high_compression_ratio_before_extracting(self):
+        source_buffer = io.BytesIO()
+        with zipfile.ZipFile(source_buffer, 'w', zipfile.ZIP_DEFLATED) as archive:
+            archive.writestr('repo-main/skill/SKILL.md', b'---\nname: safe\n---\n')
+            archive.writestr('repo-main/skill/bomb.bin', b'0' * (1024 * 1024))
+
+        source_buffer.seek(0)
+        target_buffer = io.BytesIO()
+        with (
+            zipfile.ZipFile(source_buffer, 'r') as source_zip,
+            zipfile.ZipFile(target_buffer, 'w', zipfile.ZIP_DEFLATED) as target_zip,
+        ):
+            with pytest.raises(ValueError, match='compression-ratio limit'):
+                self._service()._copy_github_skill_directory_to_zip(
+                    source_zip,
+                    target_zip,
+                    'repo-main/skill',
+                    'safe',
+                )