Add shared helper to abbreviate orchestration task specs for brief listi

- Normalizes whitespace and caps spec length at 160 chars, flagging
  truncation separately from whitespace-only changes
- Truncates on UTF-16 code point boundaries to avoid splitting
  surrogate pairs and emitting malformed strings

src/shared/orchestration-task-summary.test.ts

@@ -0,0 +1,38 @@
+import { describe, expect, it } from 'vitest'
+import { abbreviateOrchestrationTasks } from './orchestration-task-summary'
+
+describe('abbreviateOrchestrationTasks', () => {
+  it('collapses whitespace and caps long task specs', () => {
+    const [task] = abbreviateOrchestrationTasks([
+      { id: 'task_1', spec: `First line\n\n${'detail '.repeat(40)}` }
+    ])
+
+    expect(task.id).toBe('task_1')
+    expect(task.spec).not.toContain('\n')
+    expect(task.spec).toHaveLength(160)
+    expect(task.spec.endsWith('…')).toBe(true)
+    expect(task.spec_truncated).toBe(true)
+  })
+
+  it('preserves a short one-line spec', () => {
+    const [task] = abbreviateOrchestrationTasks([{ spec: 'Short task' }])
+
+    expect(task).toEqual({ spec: 'Short task', spec_truncated: false })
+  })
+
+  it('does not report whitespace normalization as truncation', () => {
+    const [task] = abbreviateOrchestrationTasks([{ spec: 'Short\n\n  task' }])
+
+    expect(task).toEqual({ spec: 'Short task', spec_truncated: false })
+  })
+
+  it('does not split a surrogate pair at the truncation boundary', () => {
+    // 158 chars + an astral emoji spanning UTF-16 units 158-159: a naive
+    // slice(0, 159) would cut the pair and leave a lone high surrogate.
+    const [task] = abbreviateOrchestrationTasks([{ spec: `${'a'.repeat(158)}😀${'b'.repeat(40)}` }])
+
+    expect(task.spec_truncated).toBe(true)
+    expect(task.spec.isWellFormed()).toBe(true)
+    expect(task.spec.endsWith('…')).toBe(true)
+  })
+})

src/shared/orchestration-task-summary.ts

@@ -0,0 +1,25 @@
+const TASK_SPEC_BRIEF_LENGTH = 160
+
+export function abbreviateOrchestrationTasks<T extends { spec: string }>(
+  tasks: readonly T[]
+): (T & { spec_truncated: boolean })[] {
+  return tasks.map((task) => {
+    const spec = task.spec.replace(/\s+/g, ' ').trim()
+    const truncated = spec.length > TASK_SPEC_BRIEF_LENGTH
+    return {
+      ...task,
+      spec: truncated ? `${truncateAtCodePoint(spec).trimEnd()}…` : spec,
+      // Why: whitespace normalization alone is not truncation; flagging it
+      // would make agents re-fetch full specs that --brief already shows.
+      spec_truncated: truncated
+    }
+  })
+}
+
+function truncateAtCodePoint(spec: string): string {
+  const sliced = spec.slice(0, TASK_SPEC_BRIEF_LENGTH - 1)
+  // Why: a cut through a surrogate pair leaves a lone high surrogate that
+  // strict JSON consumers reject; drop it rather than emit malformed UTF-16.
+  const lastUnit = sliced.charCodeAt(sliced.length - 1)
+  return lastUnit >= 0xd800 && lastUnit <= 0xdbff ? sliced.slice(0, -1) : sliced
+}