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.

packages/core/agent-loop/tests/config-session-id.spec.ts

@@ -359,7 +359,7 @@ describe('config-driven session id', () => {
     await ctx2.fiber.dispose()
   })
 
-  it('config-driven resumeSessionId continues a persisted session (env-var resume)', async () => {
+  it('config-driven resumeSessionId continues a persisted session', async () => {
     const root = await mkdtemp(join(tmpdir(), 'dsh-cfg-resume-'))
     dirs.push(root)