fix(projects): require creation directories and show remote directory links

Require a root folder in the local project creation dialog and IPC while preserving updates to historical projects with blank paths. Show remote symlinks whose targets are directories and resolve their canonical paths when browsing.

Validation: focused UI, contract, IPC and SSH tests passed; typecheck and lint passed. Verified directory links on the shared Linux Host. Full test run timed out after a Magic Notes storage timing failure.

Release note: 新建本地项目必须选择目录；远程项目选择目录时可查看并进入指向目录的符号链接。

src/main/ipc.test.ts

@@ -6464,6 +6464,33 @@ describe('registerIpcHandlers agent terminal state', () => {
     }
   })
 
+  it('requires a directory through project creation IPC while preserving blank-path updates', async () => {
+    const database = new AssistantDatabase(':memory:')
+    database.initialize(process.cwd())
+    const harness = createHarness({}, undefined, 'always', undefined, false, undefined, undefined, undefined,
+      false, undefined, undefined, undefined, undefined, database)
+    try {
+      const event = trustedEvent(harness.webContents)
+      const create = electronMocks.handlers.get(ipcChannels.projectsCreate)!
+      const input = { name: 'Directory project', description: '', rootPath: '', defaultWorkMode: 'ask' as const }
+      const initialCount = database.listProjects().length
+      for (const rootPath of ['', '   ']) {
+        expect(() => create(event, { ...input, rootPath })).toThrow()
+      }
+      expect(database.listProjects()).toHaveLength(initialCount)
+      const created = create(event, { ...input, rootPath: ` ${process.cwd()} ` }) as AssistantProject
+      expect(database.getProject(created.id).rootPath).toBe(process.cwd())
+      database.updateProject(created.id, input)
+      await electronMocks.handlers.get(ipcChannels.projectsUpdate)!(event, {
+        projectId: created.id, input: { ...input, name: 'Renamed historical project' }
+      })
+      expect(database.getProject(created.id)).toMatchObject({ name: 'Renamed historical project', rootPath: '' })
+    } finally {
+      await harness.dispose()
+      database.close()
+    }
+  })
+
   it.each(['global', 'projects'] as const)('collects supervision within the exact UI timeRange before limits (%s)', async (kind) => {
     vi.useFakeTimers({ toFake: ['Date'] })
     vi.setSystemTime(new Date('2026-09-22T08:00:00.000Z'))