feat(wire): PdfOcrProgress.Finished + ingest_progress.v1 additive 4 fields

v0.20.x ingest log feature 의 wire side. additive minor cascade:

  * PdfOcrProgress::Finished + IngestEvent::PdfOcrFinished 의 4 field:
      - image_byte_size: Option<u64>
      - image_width:     Option<u32>
      - image_height:    Option<u32>
      - failure_reason:  Option<String>
  * docs/wire-schema/v1/ingest_progress.schema.json — 4 추가 property
    (모두 optional, required 변경 없음 = additive minor)
  * integrations/claude-code/kebab/SKILL.md — wire schema description 동기

기존 ingest_progress.v1 consumer (CLI wire dump, integration test
fixture, kebab-cli wire_search/wire_ask) 는 4 추가 field 의
Option::None 으로 backward-compat. version bump 0 (additive minor =
binary-version cascade trigger 아님 per CLAUDE.md §Versioning cascade).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/kebab-app/src/ingest_progress.rs

@@ -99,6 +99,18 @@ pub enum IngestEvent {
         chars: u32,
         ocr_engine: String,
         skipped: bool,
+        /// v0.20.x ingest log: raster image byte size (additive minor, optional).
+        #[serde(skip_serializing_if = "Option::is_none")]
+        image_byte_size: Option<u64>,
+        /// v0.20.x ingest log: raster image width in pixels (additive minor, optional).
+        #[serde(skip_serializing_if = "Option::is_none")]
+        image_width: Option<u32>,
+        /// v0.20.x ingest log: raster image height in pixels (additive minor, optional).
+        #[serde(skip_serializing_if = "Option::is_none")]
+        image_height: Option<u32>,
+        /// v0.20.x ingest log: OCR failure reason (additive minor, optional).
+        #[serde(skip_serializing_if = "Option::is_none")]
+        failure_reason: Option<String>,
     },
 }