refactor(core): 빈 re-export shim crate kebab-embed/kebab-llm → kebab-core 흡수

kebab-embed/kebab-llm 은 "새 type 없음"을 자처한 순수 re-export 셸이었다
(trait 은 이미 kebab-core 소유, mock + test helper 만 보유). "kebab-core
재구성 시 안정 surface" 라는 명분은 1인 RAG 엔 speculative YAGNI. 흡수:

- kebab-core 에 default-OFF `mock` feature + src/mock.rs (MockEmbedder,
  MockLanguageModel, assert_vector_shape/assert_unit_norm/assert_finish_chunk
  을 kebab_core:: → crate:: import 만 바꿔 verbatim 이동).
- production import 2곳(kebab-embed-local, kebab-llm-local) +
  test import 다수(search/rag/parse-image/embed-local) 를 kebab_core 로 repoint.
  mock 쓰는 crate 는 dev-dep 에 features=["mock"] (default 빌드 무영향).
- shim 자체 테스트: mock 동작 테스트는 kebab-core/tests/ 로 이동,
  reexports.rs(셸 재수출 테스트)는 폐기.
- crates/kebab-embed, crates/kebab-llm 삭제 + workspace member/deps 정리.
- ARCHITECTURE/HANDOFF/component README 의 crate 그래프·표·rationale 갱신
  (22 → 20 crates). llm-local 의 broken intra-doc link 2건도 정리.

trait surface·동작 불변 (test-only + import-rename). workspace build 는 mock
default-OFF 라 mock 코드 미컴파일. 적대적 검증 3렌즈(build-test-integrity +
behavior-identity[mock byte-identical] + dead-crate-completeness) 통과,
clippy --workspace -D warnings 클린.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012Mc6W1fgsrbFKTsqA6P8La

Cargo.lock

@@ -4248,10 +4248,8 @@ dependencies = [
  "kebab-chunk",
  "kebab-config",
  "kebab-core",
- "kebab-embed",
  "kebab-embed-local",
  "kebab-embed-ollama",
- "kebab-llm",
  "kebab-llm-local",
  "kebab-nli",
  "kebab-parse-code",
@@ -4340,6 +4338,7 @@ version = "0.31.0"
 dependencies = [
  "anyhow",
  "blake3",
+ "proptest",
  "serde",
  "serde_json",
  "serde_json_canonicalizer",
@@ -4348,20 +4347,6 @@ dependencies = [
  "unicode-normalization",
 ]
 
-[[package]]
-name = "kebab-embed"
-version = "0.31.0"
-dependencies = [
- "anyhow",
- "blake3",
- "kebab-config",
- "kebab-core",
- "proptest",
- "serde",
- "thiserror 2.0.18",
- "tracing",
-]
-
 [[package]]
 name = "kebab-embed-local"
 version = "0.31.0"
@@ -4369,7 +4354,7 @@ dependencies = [
  "anyhow",
  "fastembed",
  "kebab-config",
- "kebab-embed",
+ "kebab-core",
  "serde_json",
  "tempfile",
  "tracing",
@@ -4409,15 +4394,6 @@ dependencies = [
  "uuid",
 ]
 
-[[package]]
-name = "kebab-llm"
-version = "0.31.0"
-dependencies = [
- "anyhow",
- "kebab-core",
- "proptest",
-]
-
 [[package]]
 name = "kebab-llm-local"
 version = "0.31.0"
@@ -4425,7 +4401,6 @@ dependencies = [
  "anyhow",
  "kebab-config",
  "kebab-core",
- "kebab-llm",
  "reqwest 0.12.28",
  "serde",
  "serde_json",
@@ -4504,7 +4479,6 @@ dependencies = [
  "kamadak-exif",
  "kebab-config",
  "kebab-core",
- "kebab-llm",
  "kebab-llm-local",
  "ndarray",
  "ort",
@@ -4559,7 +4533,6 @@ dependencies = [
  "blake3",
  "kebab-config",
  "kebab-core",
- "kebab-llm",
  "kebab-nli",
  "kebab-search",
  "kebab-store-sqlite",
@@ -4581,7 +4554,6 @@ dependencies = [
  "globset",
  "kebab-config",
  "kebab-core",
- "kebab-embed",
  "kebab-store-sqlite",
  "kebab-store-vector",
  "rusqlite",