feat(tui): add safe session resume flow

apps/cli/README.md

@@ -5,7 +5,7 @@ The `dsh` command-line entry follows the `apps/` assembly tier: `apps/*` are pro
 The TUI surface:
 
 - boots the shipped default config (`examples/tui-agent/cordis.yml`) or an explicit config argument, through [`dsh-app-boot`](../../packages/ui/app-boot/README.md);
-- resumes a persisted session with `dsh --resume <session-id>` — the form the TUI prints on exit and lists under `/resume`; the flag sets `RESUME_SESSION_ID` before boot so the shipped config rehydrates that session, and a missing or unreadable id fails loud and exits nonzero;
+- resumes a persisted session with `dsh --resume <session-id>` and, when the Node host exposes `process.execve`, supplies the TUI's in-place handoff host: after selector preflight and current-session flush, the host disposes the app and atomically replaces the process with a normalized resume flag so only one runtime owns the terminal; runtimes without process replacement keep the displayed command fallback, the flag still sets `RESUME_SESSION_ID` before boot, and a missing or unreadable id fails loud instead of creating a fresh session;
 - treats the **invoking directory** as the workspace — sessions, relative paths, and workspace instructions resolve from the cwd;
 - tells the agent where its own source lives: after boot it adds a prompt section naming this harness checkout, resolved from the launcher's real path so it holds under a PATH symlink and an arbitrary cwd, so the self-referential `cordis` toolset can read and modify it;
 - applies the personal overlay from `~/.dsh` (see [app-boot's Personal config](../../packages/ui/app-boot/README.md#personal-config)): `.env` fills environment gaps (ambient > project `.env` > personal `.env`), `config.yaml` patches the booted tree.

apps/cli/package.json

@@ -29,6 +29,8 @@
     "@deepseek-ai/dsh-host-runtime": "workspace:^",
     "@deepseek-ai/dsh-host-webserver": "workspace:^",
     "@deepseek-ai/dsh-paths": "workspace:^",
-    "@deepseek-ai/dsh-session": "workspace:^"
+    "@deepseek-ai/dsh-session": "workspace:^",
+    "@deepseek-ai/dsh-tui": "workspace:^",
+    "cordis": "^4.0.0-rc.7"
   }
 }

apps/cli/src/tui.ts

@@ -19,9 +19,12 @@ import {
   loadEnv,
   loadPersonalPatches,
   parseResumeArg,
+  replaceResumeArg,
   resolveConfigPath,
 } from '@deepseek-ai/dsh-app-boot'
 import { resolveDshHome } from '@deepseek-ai/dsh-paths'
+import type { Context } from 'cordis'
+import type { TuiResumeHost } from '@deepseek-ai/dsh-tui'
 
 const NAME = 'dsh'
 
@@ -65,7 +68,39 @@ export async function runTui(argv: string[]): Promise<void> {
   // after loadEnv and before boot reads it through the config's `!!js`.
   const { resumeSessionId, rest } = parseResumeArg(argv)
   if (resumeSessionId !== undefined) process.env[RESUME_SESSION_ID_ENV] = resumeSessionId
-  const ctx = await boot(NAME, resolveConfigPath(rest[0] ?? DEFAULT_CONFIG, undefined), loadPersonalPatches(NAME))
+  const entry = process.argv[1]
+  const execve = process.execve?.bind(process)
+  const app: { current?: Context } = {}
+  const resumeHost: TuiResumeHost | undefined = entry === undefined || execve === undefined ? undefined : {
+    async handoff(sessionId): Promise<never> {
+      const current = app.current
+      if (current === undefined) throw new Error(`${NAME}: app boot has not completed`)
+      const nextArgv = [
+        process.execPath,
+        ...process.execArgv,
+        entry,
+        ...replaceResumeArg(process.argv.slice(2), sessionId),
+      ]
+      process.env[RESUME_SESSION_ID_ENV] = sessionId
+      try {
+        await current.fiber.dispose()
+        execve(process.execPath, nextArgv, process.env)
+        throw new Error('process replacement returned unexpectedly')
+      } catch (error) {
+        process.stderr.write(`${NAME}: resume handoff failed after terminal release: ${String(error)}\n`)
+        process.exit(1)
+      }
+    },
+  }
+  const ctx = await boot(
+    NAME,
+    resolveConfigPath(rest[0] ?? DEFAULT_CONFIG, undefined),
+    loadPersonalPatches(NAME),
+    (hostCtx) => {
+      if (resumeHost !== undefined) hostCtx.provide('tuiResumeHost', resumeHost)
+    },
+  )
+  app.current = ctx
   addHarnessSourceSection(ctx, SOURCE_ROOT)
 }
 /* v8 ignore stop */

apps/cli/tsconfig.json

@@ -26,6 +26,9 @@
     {
       "path": "../../packages/ui/app-boot"
     },
+    {
+      "path": "../../packages/ui/tui"
+    },
     {
       "path": "../../packages/util/paths"
     },