refactor(schedule): simplify request zone authority

packages/context/time-context/tests/request-zone.spec.ts

@@ -0,0 +1,54 @@
+import { describe, expect, it } from 'vitest'
+import { createUserMessage } from '@deepseek-ai/dsh-llm'
+import {
+  deriveClientTimeZoneContext,
+  renderTimeZoneContext,
+} from '@deepseek-ai/dsh-time-context'
+
+function request(clientTimeZone?: unknown) {
+  return createUserMessage({
+    content: [{ type: 'text', text: 'request' }],
+    source: clientTimeZone === undefined
+      ? { kind: 'user' }
+      : { kind: 'user', clientTimeZone } as never,
+  })
+}
+
+describe('request-zone derivation', () => {
+  it('derives missing, one resolved zone, and sorted unique mixed zones', () => {
+    const plugin = createUserMessage({
+      content: [],
+      source: { kind: 'plugin', plugin: 'fixture' },
+    })
+    expect(deriveClientTimeZoneContext([plugin, request(), request(1)])).toEqual({ kind: 'missing' })
+    expect(deriveClientTimeZoneContext([
+      request('Asia/Shanghai'),
+      request('Asia/Shanghai'),
+    ])).toEqual({ kind: 'resolved', timeZone: 'Asia/Shanghai' })
+    expect(deriveClientTimeZoneContext([
+      request('Asia/Shanghai'),
+      request('America/New_York'),
+    ])).toEqual({
+      kind: 'mixed',
+      timeZones: ['America/New_York', 'Asia/Shanghai'],
+    })
+  })
+
+  it('renders resolved, mixed, and unavailable policy lines', () => {
+    expect(renderTimeZoneContext('Asia/Shanghai', {
+      kind: 'resolved',
+      timeZone: 'Asia/Shanghai',
+    })).toBe(
+      'Session time zone: Asia/Shanghai.\nClient time zone for this request: Asia/Shanghai.',
+    )
+    expect(renderTimeZoneContext('UTC', {
+      kind: 'mixed',
+      timeZones: ['America/New_York', 'UTC'],
+    })).toBe(
+      'Session time zone: UTC.\nClient time zone for this request: mixed ["America/New_York","UTC"].',
+    )
+    expect(renderTimeZoneContext(undefined, { kind: 'missing' })).toBe(
+      'Session time zone: unavailable.\nClient time zone for this request: missing.',
+    )
+  })
+})