feat(wire): additive minor — IngestEvent kind 의 pdf_ocr_* + ingest_report.items[] 의 pdf_ocr_pages/ms_total + skipped field carry (Step 6 M-4/M-2)

Step 7 (Group G) of v0.20.0 sub-item 1 (scanned PDF OCR) plan +
Step 6 code reviewer Important M-4 (skipped field carry) + Minor M-2
(ordering invariant doc) fix.

G3 — JSON Schema sync (additive minor — schema_version 보존):

ingest_progress.schema.json:
- kind enum 2 추가: pdf_ocr_started + pdf_ocr_finished.
- 새 field: page (1-based PDF page), ocr_engine (engine_name), skipped (bool).
- 기존 ms / chars field 의 description 갱신 (pdf_ocr_finished carry 추가).

ingest_report.schema.json:
- items.items.properties 신규 정의 (이전 stub ["array", "null"] 만).
- pdf_ocr_pages + pdf_ocr_ms_total (nullable integer).
- 모든 기존 IngestItem field 도 명시화 (kind, doc_path, byte_len, ...).

Step 6 reviewer M-4 (Important) — skipped field carry:
- IngestEvent::PdfOcrFinished 에 skipped: bool 추가.
- ingest_one_pdf_asset 의 emit closure (lib.rs:~1864) 가 source
  PdfOcrProgress::Finished { skipped } 를 discard 않고 propagate.

Step 6 reviewer M-2 (Minor) — ordering invariant doc:
- crates/kebab-app/src/ingest_progress.rs 의 ordering text 갱신:
  ScanStarted < ScanCompleted < (AssetStarted [< (PdfOcrStarted <
  PdfOcrFinished)*] < AssetFinished)* < (Completed | Aborted).

.md doc (docs/wire-schema/v1/*.md) 부재 — plan §3 Step 7 G3 의 .md
deliverable retro N/A (해당 file 0).

spec:  docs/superpowers/specs/2026-05-27-pdf-scanned-ocr-spec.md
plan:  docs/superpowers/plans/2026-05-27-pdf-scanned-ocr-plan.md (Step 7 G3)
prior: b9ee09f (Step 6 wiring) + Step 6 reviewer M-4/M-2 권고
contract: §9 (additive minor wire bump — schema_version 보존)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

crates/kebab-app/src/ingest_progress.rs

@@ -46,10 +46,13 @@ pub struct AggregateCounts {
 /// Ordering invariant per design §2.4a:
 ///
 /// ```text
-/// ScanStarted < ScanCompleted < (AssetStarted < AssetFinished)*
-///                             < (Completed | Aborted)
+/// ScanStarted < ScanCompleted
+///   < (AssetStarted [< (PdfOcrStarted < PdfOcrFinished)*] < AssetFinished)*
+///   < (Completed | Aborted)
 /// ```
 ///
+/// `[]` = optional, per-PDF asset only (v0.20.0 sub-item 1).
+///
 /// Embed-batch events (`embed_batch_started` / `embed_batch_finished`
 /// in §2.4a) are reserved for a future iteration and are not emitted
 /// by this task; the spec calls them out as "임의 위치" (optional).
@@ -88,11 +91,14 @@ pub enum IngestEvent {
     /// PDF page 별 OCR 시작 시 emit. v0.20.0 sub-item 1.
     PdfOcrStarted { page: u32 },
     /// PDF page 별 OCR 종료 시 emit. v0.20.0 sub-item 1.
+    /// `skipped` = `true` 일 시 OCR 미수행 (DCTDecode 부재 또는 engine 실패).
+    /// `chars = 0` 만으로는 "skip" 과 "0-char OCR result" 구분 불가, `skipped` field 가 명시적.
     PdfOcrFinished {
         page: u32,
         ms: u64,
         chars: u32,
         ocr_engine: String,
+        skipped: bool,
     },
 }