refactor(cli): bail early in the arg adapter instead of returning errors as data

Address review and cut ceremony: the adapter no longer models help/version/
errors as DshInvocation members. Commander owns those under exitOverride — it
prints usage or the diagnostic and one try/catch in parseDshArgs turns the
thrown CommanderError into process.exit with the intended code. bin.ts drops its
help/version/error cases; the union is the three real modes.

Domain checks bail via command.error(print + exit 1): --prompt rejects an empty
task or a stray config/--resume, empty --resume= fails loud, and --host/--port
are validated. A repeated --resume or a flag captured as a value is Commander's
standard behavior, left alone (a bad id fails loud downstream). dsh --help
discloses web via addHelpText. Net: args.ts 185 -> 112 lines.

Also fixes review nits: built-bin e2e resolves on `close`; the /resume handoff
uses `dsh --resume=<id> -- <config>` so a config named `web` stays a positional;
and stale prose (cordis.yml comment, app-boot module doc + duplicate JSDoc,
ui/README, two feature notes, an agent-loop test name) tracks the shipped state.
Removes tui-demo's now-dead plugin-include dep and vendor/loader + app-boot
tsconfig references.

apps/cli/src/bin.ts

@@ -3,8 +3,8 @@
  * dsh — command-line entry. Parses argv once through the Commander adapter and
  * switches on the resolved mode; dynamic imports keep unrelated modes out of
  * each dispatch path. `web` and headless prompts run their own module;
- * everything else opens the TUI. `--help`/`--version` print and exit 0; a parse
- * error prints to stderr and exits 1.
+ * everything else opens the TUI. The adapter itself prints and exits for
+ * `--help`/`--version`/a parse error, so only a valid mode reaches the switch.
  * @module @deepseek-ai/dsh/bin
  */
 
@@ -45,13 +45,6 @@ switch (invocation.mode) {
     await runTui(invocation.config, invocation.resume)
     break
   }
-  case 'help':
-  case 'version':
-    process.stdout.write(invocation.text)
-    process.exit(0)
-  case 'error':
-    process.stderr.write(`${invocation.message}\n`)
-    process.exit(1)
   default:
     invocation satisfies never
     throw new Error(`dsh: unhandled invocation mode ${JSON.stringify(invocation)}`)