fix(skill): harden the fast path against the review findings

Fifteen review findings on the fast-path rewrite plus one caught live, all
verified against a real 1.18.1 server before landing:

- sendwait picks a fresh seq (the epoch second) instead of a fixed 2, so a
  second prompt to the same worker is typed instead of silently swallowed as
  an already-applied duplicate; explicit seq remains for deliberate resends
- sendwait self-heals stranded delivery: an Ink repaint occasionally eats the
  Enter (observed live), so a timed-out short first wait sends one bare \r and
  re-waits by resending the identical frame as a tagged duplicate
- spawn_worker verifies the resolved casePath carries Codeman hooks (the same
  /api/hook-event marker the server checks), refusing names that resolve to
  linked or pre-existing hook-less directories instead of running the job in
  what may be the user's real repo
- spawn_worker probes the trust dialog after a short 5s composer wait, not the
  full 45s, restoring the ladder staging verbs.md documents; on a readiness
  miss it deletes the half-spawned session and returns 1 with empty stdout,
  so a prompt can never be typed blind into a trust dialog
- spawn_workers refuses duplicate case names and empty argument lists, and
  keys result files by index
- section 1 is bash 3.2 compatible (indexed arrays, no declare -A), prints the
  full delivered/timedOut/signal tuple per worker with an explicit line for a
  missing result, deletes only workers whose turn really ended (a timeout
  means still working), cleans up spawned siblings when any spawn fails, and
  guards its mktemp
- last_text takes the previous answer as an optional second argument for
  consecutive-turn reads (the transcript briefly serves the prior answer
  after a stop, observed live)
- the stale duplicate bullets in section 1's closing list are gone
- reference/verbs.md joins the mode-list drift guard's file list
- README's skill inventory covers verbs.md and the new SKILL.md shape
- the changeset is minor so the shipped release matches the 1.19.0 stamp

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

test/agent-skill-mode-lists.test.ts

@@ -45,7 +45,13 @@ import type { SessionMode } from '../src/types/session.js';
 
 const HERE = fileURLToPath(new URL('.', import.meta.url));
 const SKILL_DIR = join(HERE, '../skills/codeman');
-const SKILL_FILES = ['SKILL.md', 'reference/endpoints.md', 'reference/messaging.md', 'reference/recipes.md'];
+const SKILL_FILES = [
+  'SKILL.md',
+  'reference/endpoints.md',
+  'reference/messaging.md',
+  'reference/recipes.md',
+  'reference/verbs.md',
+];
 
 /** Modes the API actually accepts, read off the schema rather than restated here. */
 function schemaModes(schema: typeof CreateSessionSchema | typeof QuickStartSchema): SessionMode[] {