feat(12-03): connection-ID routing, rename, session folder memory, thin views

- Route /cloud/:connectionId/:folderId replaces /cloud/:provider/:folderId
- api/cloud.js: getCloudFoldersByConnectionId + renameCloudConnection
- cloudConnections store: rename, selectConnection, setBrowseState, defaultDisplayName, session storage helpers
- CloudStorageView: thin — passes connectionRoots to StorageBrowser
- CloudFolderView: thin — uses connectionId param, never provider slug
- SettingsCloudTab: inline rename input for each active connection
- 27 tests pass: store, view, settings

frontend/src/stores/__tests__/cloudConnections.test.js

@@ -1,4 +1,4 @@
-import { describe, it, expect, vi, beforeEach } from 'vitest'
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest'
 import { setActivePinia, createPinia } from 'pinia'
 
 // Mock api/client.js — no real HTTP calls in unit tests (CLAUDE.md W4)
@@ -7,14 +7,22 @@ vi.mock('../../api/client.js', () => ({
   disconnectCloud: vi.fn(),
   connectWebDav: vi.fn(),
   updateDefaultStorage: vi.fn(),
+  renameCloudConnection: vi.fn(),
+  getCloudFoldersByConnectionId: vi.fn(),
 }))
 
-import { useCloudConnectionsStore } from '../cloudConnections.js'
+import { useCloudConnectionsStore, saveLastFolder, loadLastFolder } from '../cloudConnections.js'
 import * as api from '../../api/client.js'
 
 beforeEach(() => {
   setActivePinia(createPinia())
   vi.clearAllMocks()
+  // Clear sessionStorage between tests
+  sessionStorage.clear()
+})
+
+afterEach(() => {
+  sessionStorage.clear()
 })
 
 describe('useCloudConnectionsStore', () => {
@@ -56,4 +64,95 @@ describe('useCloudConnectionsStore', () => {
     await store.disconnectAll()
     expect(store.connections).toHaveLength(0)
   })
+
+  // Rename tests
+  it('rename updates the connection in state on success', async () => {
+    api.renameCloudConnection.mockResolvedValue({
+      id: 'conn-1', provider: 'google_drive', display_name: 'My Drive',
+    })
+    const store = useCloudConnectionsStore()
+    store.connections = [{ id: 'conn-1', provider: 'google_drive', display_name: 'Google Drive' }]
+    await store.rename('conn-1', 'My Drive')
+    expect(store.connections[0].display_name).toBe('My Drive')
+    expect(api.renameCloudConnection).toHaveBeenCalledWith('conn-1', 'My Drive')
+  })
+
+  it('rename rejects on empty display name', async () => {
+    const store = useCloudConnectionsStore()
+    await expect(store.rename('conn-1', '')).rejects.toThrow()
+  })
+
+  it('rename rejects on whitespace-only display name', async () => {
+    const store = useCloudConnectionsStore()
+    await expect(store.rename('conn-1', '   ')).rejects.toThrow()
+  })
+
+  it('rename propagates API error', async () => {
+    api.renameCloudConnection.mockRejectedValue(new Error('API error'))
+    const store = useCloudConnectionsStore()
+    store.connections = [{ id: 'conn-1', provider: 'google_drive', display_name: 'Google Drive' }]
+    await expect(store.rename('conn-1', 'New Name')).rejects.toThrow('API error')
+  })
+
+  // Two same-provider connections render as separate roots
+  it('two google_drive connections render as separate roots with UUID suffixes in defaultDisplayName', () => {
+    const store = useCloudConnectionsStore()
+    store.connections = [
+      { id: 'aabb-ccdd-1', provider: 'google_drive', display_name: null },
+      { id: 'eeff-gggg-2', provider: 'google_drive', display_name: null },
+    ]
+    const nameA = store.defaultDisplayName(store.connections[0])
+    const nameB = store.defaultDisplayName(store.connections[1])
+    // Both should contain "Google Drive" and a 4-char suffix
+    expect(nameA).toContain('Google Drive')
+    expect(nameB).toContain('Google Drive')
+    expect(nameA).toContain('aabb')
+    expect(nameB).toContain('eeff')
+  })
+
+  it('single connection has no suffix in defaultDisplayName', () => {
+    const store = useCloudConnectionsStore()
+    store.connections = [{ id: 'conn-1', provider: 'google_drive' }]
+    expect(store.defaultDisplayName(store.connections[0])).toBe('Google Drive')
+  })
+
+  // Connection UUID based URLs
+  it('selectConnection sets selectedConnectionId', () => {
+    const store = useCloudConnectionsStore()
+    store.connections = [{ id: 'uuid-123', provider: 'onedrive' }]
+    store.selectConnection('uuid-123')
+    expect(store.selectedConnectionId).toBe('uuid-123')
+    expect(store.selectedConnection?.id).toBe('uuid-123')
+  })
+
+  // Session storage for folder navigation
+  it('saveLastFolder stores folder in sessionStorage', () => {
+    saveLastFolder('conn-abc', 'Documents/Work')
+    expect(sessionStorage.getItem('docuvault:cloud:folder:conn-abc')).toBe('Documents/Work')
+  })
+
+  it('loadLastFolder retrieves stored folder', () => {
+    sessionStorage.setItem('docuvault:cloud:folder:conn-xyz', 'Photos')
+    expect(loadLastFolder('conn-xyz')).toBe('Photos')
+  })
+
+  it('saveLastFolder removes key for root folder', () => {
+    sessionStorage.setItem('docuvault:cloud:folder:conn-abc', 'Docs')
+    saveLastFolder('conn-abc', 'root')
+    expect(sessionStorage.getItem('docuvault:cloud:folder:conn-abc')).toBeNull()
+  })
+
+  it('loadLastFolder returns null when nothing stored', () => {
+    expect(loadLastFolder('nonexistent')).toBeNull()
+  })
+
+  it('sessionStorage stores only folder references, not tokens', () => {
+    // Ensure save only stores the folderId string under the namespaced key
+    saveLastFolder('conn-123', 'Projects/Secret')
+    const stored = sessionStorage.getItem('docuvault:cloud:folder:conn-123')
+    expect(stored).toBe('Projects/Secret')
+    // Stored value is a plain string path, not a JSON object with credentials
+    expect(typeof stored).toBe('string')
+    expect(stored.startsWith('{')).toBe(false)
+  })
 })