refactor(config): v3 경로 call-site sweep (kebab-app/kebab-eval/kebab-parse-image)

부모 경로에 .ingest 삽입(leaf 구조체 불변). src + 테스트 call-site 전부.
kebab-cli 테스트의 v2 TOML fixture 는 from_file 자동변환(T6) 경로 검증용으로 유지.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

crates/kebab-app/tests/common/mod.rs

@@ -62,8 +62,8 @@ impl TestEnv {
         // Drop in a small chunk policy so the fixture's small files
         // emit at least a couple of chunks even with overlap_tokens
         // honored.
-        config.chunking.target_tokens = 80;
-        config.chunking.overlap_tokens = 20;
+        config.ingest.chunking.target_tokens = 80;
+        config.ingest.chunking.overlap_tokens = 20;
 
         Self {
             temp,