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>

integrations/claude-code/kebab/SKILL.md

@@ -145,7 +145,7 @@ Claude Code spawns `kebab mcp` at session start; the process stays alive across
 - Pagination: `search_response.v1.next_cursor` is opaque base64 — pass back as `--cursor` (CLI) or `cursor` (MCP) for the next page. `null` means no more hits. `corpus_revision` mismatch returns `error.v1.code = stale_cursor` — re-issue search to obtain a fresh cursor.
 - `search_response.v1.truncated = true` means budget forced snippet shortening or k reduction. Independent of `next_cursor`: widen `max_tokens` for fuller snippets, follow `next_cursor` for more hits, or both.
 - `ask`'s `citations[]` mirrors `search_hit.v1` minus retrieval internals — same `doc_path` / `citation` shape.
-- Schema reference lives in the kebab repo at `docs/wire-schema/v1/*.schema.json` if a field is unclear.
+- Schema reference lives in the kebab repo at `docs/wire-schema/v1/*.schema.json` if a field is unclear. v0.20.x additive minor: `ingest_progress.v1` `pdf_ocr_finished` events carry 4 optional new fields (`image_byte_size`, `image_width`, `image_height`, `failure_reason`) — absent on pre-v0.20 events (backward compat).
 - `search_hit.v1` and `answer.v1.citations[]` carry `indexed_at` (RFC3339) + `stale` (bool). When `stale == true`, the source doc hasn't been re-processed since `config.search.stale_threshold_days`. Surface this caveat to the user when summarizing — the cited snapshot may not reflect current reality.
 
 ## Capability discovery