refactor(cli): parse dsh argv through one Commander adapter

Replace the dsh CLI's three hand-rolled parsing idioms (raw argv[0]/includes
dispatch in bin.ts, per-mode node:util parseArgs in headless.ts/web.ts, and the
bespoke parseResumeArg scanner in dsh-app-boot) with a single Commander adapter
in apps/cli/src/args.ts. parseDshArgs resolves argv into a discriminated
DshInvocation union; bin.ts switches on the mode and dynamic-imports the chosen
module, which now consumes already-parsed values.

- web is a real subcommand; --host uses choices and --port an argParser range
  check, moving validation into the parser.
- --resume rejects empty and repeated forms; --prompt rejects empty; a config
  positional after --prompt and a root flag placed before web fail loud.
- adds --help/--version; removes parseResumeArg from dsh-app-boot.
- new apps/cli/tests/args.spec.ts (apps/*/tests added to vitest include,
  apps/cli/tests to tsconfig.host.json); the tui-agent keyless PTY smoke covers
  bin.ts dispatch end to end unchanged.

packages/ui/app-boot/README.md

@@ -5,7 +5,6 @@ Shared boot glue for the app bins ([`dsh-tui-demo`](../../examples/tui-demo/READ
 | Export | Role |
 |---|---|
 | `resolveConfigPath(path, snapshotMode, cwd?)` | Absolute config path; `snapshotMode === 'replay'` swaps a `cordis.yml`/`.yaml` basename for its sibling `cordis.snapshot.yml` |
-| `parseResumeArg(argv)` | Split the `--resume <id>` / `--resume=<id>` flag out of the arguments, returning `{ resumeSessionId, rest }`; a valueless, empty, or repeated flag throws so a mistyped resume fails loud instead of silently starting fresh |
 | `loadEnv(binName, dir?, warn?)` | Load the gitignored `.env` (Node `process.loadEnvFile`); absent file is fine, an unloadable one warns a single labelled line (default: stderr) |
 | `installFailLoud(binName, proc?)` | Turn a post-`boot()` unhandled Loader rejection into one labelled stderr line + `exit(1)`; returns the uninstaller (for tests) |
 | `assertEntriesLoaded(ctx, binName)` | Throw when a settled tree holds an enabled entry with no fiber (a plugin module that failed to import) |

packages/ui/app-boot/src/index.ts

@@ -36,50 +36,6 @@ export function resolveConfigPath(
   return resolve(dir, replayName)
 }
 
-/** CLI flag the interactive surface accepts to resume a persisted session by id. */
-const RESUME_FLAG = '--resume'
-
-/**
- * Split a leading `--resume <id>` / `--resume=<id>` flag out of a CLI argument
- * vector, returning the resumed session id (when the flag is present) and the
- * remaining arguments with the flag and its value removed — so a positional
- * config path stays readable regardless of the flag's position. A `--resume`
- * with no following id, an empty id (`--resume=`), or a repeated `--resume`
- * throws: a mistyped resume must fail loud, never silently start a fresh
- * session. The id is not validated here; an unknown id fails loud downstream
- * when the session cannot load.
- * @param argv - the CLI arguments after subcommand dispatch.
- * @returns the parsed resume id (or `undefined`) and the flag-stripped arguments.
- */
-export function parseResumeArg(
-  argv: readonly string[],
-): { resumeSessionId: string | undefined; rest: string[] } {
-  const rest: string[] = []
-  let resumeSessionId: string | undefined
-  let skipNext = false
-  for (const [i, arg] of argv.entries()) {
-    if (skipNext) {
-      skipNext = false
-      continue
-    }
-    const inlineValue = arg.startsWith(`${RESUME_FLAG}=`)
-    if (arg === RESUME_FLAG || inlineValue) {
-      if (resumeSessionId !== undefined) throw new Error(`${RESUME_FLAG} may be given only once`)
-      const value = inlineValue ? arg.slice(RESUME_FLAG.length + 1) : argv[i + 1]
-      // A following token that is itself resume syntax (`--resume --resume x`)
-      // is a missing id, not a session literally named `--resume…`.
-      if (value === undefined || value === '' || value === RESUME_FLAG || value.startsWith(`${RESUME_FLAG}=`)) {
-        throw new Error(`${RESUME_FLAG} requires a session id (e.g. ${RESUME_FLAG} <session-id>)`)
-      }
-      resumeSessionId = value
-      skipNext = !inlineValue // the space form consumed the following token as its value
-      continue
-    }
-    rest.push(arg)
-  }
-  return { resumeSessionId, rest }
-}
-
 /**
  * Load the optional gitignored `.env` from `dir`. Missing files fall back to the
  * ambient environment; other read failures are reported through `warn`.

packages/ui/app-boot/tests/app-boot.spec.ts

@@ -6,7 +6,7 @@ import { Context } from 'cordis'
 import SystemPrompt, { renderPrompt } from '@deepseek-ai/dsh-system-prompt'
 import {
   addHarnessSourceSection, assertEntriesLoaded, boot, HARNESS_SOURCE_SECTION,
-  installFailLoud, loadEnv, parseResumeArg, resolveConfigPath, type FailLoudProcess,
+  installFailLoud, loadEnv, resolveConfigPath, type FailLoudProcess,
 } from '../src/index.ts'
 
 const NAME = 'dsh-test-bin'
@@ -30,31 +30,6 @@ describe('resolveConfigPath', () => {
   })
 })
 
-describe('parseResumeArg', () => {
-  it('returns no resume id and passes arguments through when the flag is absent', () => {
-    expect(parseResumeArg([])).toEqual({ resumeSessionId: undefined, rest: [] })
-    expect(parseResumeArg(['custom.yml'])).toEqual({ resumeSessionId: undefined, rest: ['custom.yml'] })
-  })
-
-  it('parses the space form, the inline form, and leaves a positional config path in any position', () => {
-    expect(parseResumeArg(['--resume', 'sess-1'])).toEqual({ resumeSessionId: 'sess-1', rest: [] })
-    expect(parseResumeArg(['--resume=sess-2'])).toEqual({ resumeSessionId: 'sess-2', rest: [] })
-    expect(parseResumeArg(['--resume', 'sess-3', 'app.yml'])).toEqual({ resumeSessionId: 'sess-3', rest: ['app.yml'] })
-    expect(parseResumeArg(['app.yml', '--resume', 'sess-4'])).toEqual({ resumeSessionId: 'sess-4', rest: ['app.yml'] })
-  })
-
-  it('fails loud on a valueless, empty, or repeated flag rather than silently starting fresh', () => {
-    expect(() => parseResumeArg(['--resume'])).toThrow('--resume requires a session id')
-    expect(() => parseResumeArg(['--resume='])).toThrow('--resume requires a session id')
-    expect(() => parseResumeArg(['--resume', 'a', '--resume', 'b'])).toThrow('--resume may be given only once')
-  })
-
-  it('rejects resume syntax used as the flag value instead of resuming a session named like the flag', () => {
-    expect(() => parseResumeArg(['--resume', '--resume', 'sess'])).toThrow('--resume requires a session id')
-    expect(() => parseResumeArg(['--resume', '--resume=sess'])).toThrow('--resume requires a session id')
-  })
-})
-
 describe('loadEnv', () => {
   it('loads variables from .env in the given dir', () => {
     const dir = tmp()