Merge branch 'master' into claude/unified-environment-credentials-c8841a

Master removed the TUI package, the `meta` and `upgrade` subcommands, and
`--config-replace`, and made raw `dsh` require a `--config` overlay. Resolved
onto that shape:

- Dropped this branch's TUI edits with the surface itself, including
  `tui.cordis.yml`, `runTui`, and the TUI keyless PTY smoke.
- Dropped the `--config-replace` plumbing rather than reintroducing a flag
  master deliberately removed. The gap this branch fixed remains: `dsh -p`
  still could not name its composition, so it keeps `--config`.
- Kept this branch's deletion of the personal `$DSH_HOME/config.yaml` layer,
  which master still carried, and provided the environment snapshot in the new
  raw `runConfig` surface alongside web and headless.
- Ported the headless shutdown PTY test off the personal overlay onto a named
  `--config` file, which is what proves that flag now exists on `-p`.

apps/cli/src/web.ts

@@ -14,8 +14,9 @@ import type {} from '@deepseek-ai/dsh-system-prompt'
 import type {} from '@deepseek-ai/dsh-tool-bash'
 import type { EnvironmentSnapshot } from '@deepseek-ai/dsh-environment'
 import { AppCLIEntry } from './app-cli-entry.ts'
+import { createProcessShutdown } from './process-shutdown.ts'
 
-// The shared core every `dsh` surface mounts, plus this surface's overlay over it.
+// The shipped base plus the Web application's overlay.
 const BASE_CONFIG = fileURLToPath(new URL('../config/base.cordis.yml', import.meta.url))
 const WEB_OVERLAY = fileURLToPath(new URL('../config/web.cordis.yml', import.meta.url))
 const SOURCE_ROOT = fileURLToPath(new URL('../../..', import.meta.url))
@@ -121,17 +122,12 @@ export async function runWeb(
   const { ctx, port: boundPort } = await entry.run()
   const resolvedLocalWebUrl = localWebUrl(ctx)
 
-  let exiting = false
-  const shutdown = (code: number): void => {
-    if (exiting) return
-    exiting = true
-    void Promise.resolve(ctx.fiber.dispose()).finally(() => { process.exit(code) })
-  }
+  const shutdown = createProcessShutdown(async () => { await ctx.fiber.dispose() })
 
   // Install shutdown handling before publishing readiness: supervisors may
   // send a signal as soon as they observe the URL line.
-  process.on('SIGTERM', () => { shutdown(0) })
-  process.on('SIGINT', () => { shutdown(130) })
+  process.on('SIGTERM', () => { shutdown.interrupt(0) })
+  process.on('SIGINT', () => { shutdown.interrupt(130) })
 
   // The entry's boot-time snapshot, not a fresh sample: the printed LAN URL
   // must name an address the /api trust fence was configured with.