fix(rectification): plain-word opening with examples in the stem, plain de-duplicated step receipt (BUG-1049, BUG-1050)

- BUG-1049 (recurrence of BUG-504): the opening stem carries six examples and
  an example answer again and is server-owned on the zero-evidence opening;
  the body is two plain sentences (no 大运/盘面/代表分钟/精确到秒, no year, no
  question). Stem de-dup compares whole sentences / near-equality instead of a
  12-char prefix, which had deleted the body's examples sentence since
  aa7ccb30 (BUG-604) + dd8f35f7 (BUG-648).
- BUG-1050: plain step labels; a finished step label shows once and
  「已完成 N 步」counts shown rows; failed rows read 「…未完成」 from the
  in-progress wording.
- Skill 10.0.30 -> 10.0.31 (OpeningPolicy); 10.0.30 kept as deprecated.
- VOICE / DESIGN / CHANGELOG / BUG_HISTORY / PROGRESS / real-device checklist
  and screenshots.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017eEAG8HD3mm8gsKXgk8uU8

frontend/tests/rectification-confirmation-gate.test.ts

@@ -383,7 +383,8 @@ test("holdout not_ready forbids unique-minute copy and still blocks confirm", as
   // 原因: BUG-668 定向补事第四选项写进 Skill
   // 原值: "10.0.28" / 新值: "10.0.29" / 原因: 年月阶段改口述并禁止追问本人
   // 原值: "10.0.29" / 新值: "10.0.30" / 原因: D2 出卡句与 D4 卡上百分比规则写进 Skill（2026-09-26）
-  assert.equal(RECTIFICATION_SKILL_VERSION, "10.0.30");
+  // 原值: "10.0.30" / 新值: "10.0.31" / 原因: 开场改大白话、题干带例子和示例回答写进 Skill OpeningPolicy（BUG-1049，2026-09-26）
+  assert.equal(RECTIFICATION_SKILL_VERSION, "10.0.31");
 
   const accounting = fakeAccounting({
     ...receiptHandlers,