refactor(rename): kb crates → kebab — Cargo packages, folders, Rust modules

프로젝트 이름 `kb` → `kebab` rename 의 첫 단계.

- workspace `Cargo.toml`: members `crates/kb-*` → `crates/kebab-*`,
  repository URL `altair823/kb` → `altair823/kebab`.
- 18 crate 폴더 rename via `git mv` (history 보존).
- 각 crate `Cargo.toml`: `name = "kb-*"` → `"kebab-*"`, path deps
  `../kb-*` → `../kebab-*`.
- 모든 `.rs`: `kb_<id>` snake-case 모듈 path 18 개 (`kb_core`,
  `kb_config`, `kb_app`, `kb_cli`, `kb_eval`, `kb_search`, `kb_chunk`,
  `kb_normalize`, `kb_source_fs`, `kb_parse_md`, `kb_parse_types`,
  `kb_store_sqlite`, `kb_store_vector`, `kb_embed`, `kb_embed_local`,
  `kb_llm`, `kb_llm_local`, `kb_rag`) → `kebab_<id>` 일괄 sed (단어
  경계 \\b 사용해 영어 문장 안의 "kb" 약어 미오염).

CLI binary 이름 (`[[bin]] name = "kb"`), 환경변수 `KB_*`, XDG paths,
tracing target, 그리고 docs sweep 은 다음 commit 에서.

## 검증

- `cargo check --workspace` clean — 모든 crate 빌드 통과 후 commit.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

crates/kebab-app/tests/search_lexical.rs

@@ -0,0 +1,69 @@
+//! Lexical search integration tests. The vector / hybrid lanes are
+//! AVX-gated and live in `search_vector.rs` (`#[ignore]`).
+
+mod common;
+
+use common::TestEnv;
+
+fn lexical_query(text: &str) -> kebab_core::SearchQuery {
+    kebab_core::SearchQuery {
+        text: text.to_string(),
+        mode: kebab_core::SearchMode::Lexical,
+        k: 10,
+        filters: kebab_core::SearchFilters::default(),
+    }
+}
+
+#[test]
+fn lexical_search_returns_hits_after_ingest() {
+    let env = TestEnv::lexical_only();
+    kebab_app::ingest_with_config(env.config.clone(), env.scope(), true).unwrap();
+
+    // "Ownership" appears as a heading + paragraph in intro.md and
+    // matches FTS5 default tokenizer easily.
+    let hits =
+        kebab_app::search_with_config(env.config.clone(), lexical_query("ownership"))
+            .unwrap();
+    assert!(!hits.is_empty(), "expected ≥1 hit for 'ownership'");
+
+    for h in &hits {
+        // Lexical retriever sets embedding_model=None per spec.
+        assert!(
+            h.embedding_model.is_none(),
+            "lexical-mode hit must have None embedding_model: {h:?}"
+        );
+        assert_eq!(
+            h.retrieval.method,
+            kebab_core::SearchMode::Lexical,
+            "method label should be Lexical"
+        );
+    }
+}
+
+#[test]
+fn lexical_search_empty_query_returns_empty() {
+    let env = TestEnv::lexical_only();
+    kebab_app::ingest_with_config(env.config.clone(), env.scope(), true).unwrap();
+    let hits = kebab_app::search_with_config(env.config.clone(), lexical_query("   "))
+        .unwrap();
+    assert!(hits.is_empty(), "blank query must short-circuit empty");
+}
+
+#[test]
+fn vector_mode_with_provider_none_errors_clearly() {
+    let env = TestEnv::lexical_only();
+    kebab_app::ingest_with_config(env.config.clone(), env.scope(), true).unwrap();
+
+    let q = kebab_core::SearchQuery {
+        text: "ownership".to_string(),
+        mode: kebab_core::SearchMode::Vector,
+        k: 10,
+        filters: kebab_core::SearchFilters::default(),
+    };
+    let err = kebab_app::search_with_config(env.config.clone(), q).unwrap_err();
+    let msg = format!("{err:#}");
+    assert!(
+        msg.contains("embeddings disabled") || msg.contains("disabled"),
+        "error must mention embeddings disabled: {msg}"
+    );
+}