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-eval/tests/fixtures/eval/compare-1.json

@@ -0,0 +1,89 @@
+{
+  "aggregate_a": {
+    "citation_coverage": null,
+    "empty_result_rate": 0.0,
+    "failed_queries": 0,
+    "groundedness": 0.0,
+    "hit_at_k": {
+      "1": 0.33329999446868896,
+      "10": 0.666700005531311,
+      "3": 0.33329999446868896,
+      "5": 0.666700005531311
+    },
+    "mrr": 0.41670000553131104,
+    "recall_at_k_doc": {
+      "1": 0.33329999446868896,
+      "10": 0.666700005531311,
+      "3": 0.33329999446868896,
+      "5": 0.666700005531311
+    },
+    "refusal_correctness": null,
+    "total_queries": 3
+  },
+  "aggregate_b": {
+    "citation_coverage": null,
+    "empty_result_rate": 0.0,
+    "failed_queries": 0,
+    "groundedness": 0.0,
+    "hit_at_k": {
+      "1": 0.666700005531311,
+      "10": 1.0,
+      "3": 1.0,
+      "5": 1.0
+    },
+    "mrr": 0.833299994468689,
+    "recall_at_k_doc": {
+      "1": 0.666700005531311,
+      "10": 1.0,
+      "3": 1.0,
+      "5": 1.0
+    },
+    "refusal_correctness": null,
+    "total_queries": 3
+  },
+  "deltas": {
+    "chunker_version_match": "exact",
+    "citation_coverage": null,
+    "empty_result_rate": 0.0,
+    "groundedness": 0.0,
+    "hit_at_k": {
+      "1": 0.33340001106262207,
+      "10": 0.33329999446868896,
+      "3": 0.666700005531311,
+      "5": 0.33329999446868896
+    },
+    "mrr": 0.41659998893737793,
+    "recall_at_k_doc": {
+      "1": 0.33340001106262207,
+      "10": 0.33329999446868896,
+      "3": 0.666700005531311,
+      "5": 0.33329999446868896
+    },
+    "refusal_correctness": null
+  },
+  "per_query": [
+    {
+      "a_hit_rank": 1,
+      "b_hit_rank": 2,
+      "kind": "loss",
+      "note": "rank 1→2",
+      "query_id": "q-001"
+    },
+    {
+      "a_hit_rank": 4,
+      "b_hit_rank": 1,
+      "kind": "win",
+      "note": "rank 4→1",
+      "query_id": "q-002"
+    },
+    {
+      "a_hit_rank": null,
+      "b_hit_rank": 1,
+      "kind": "win",
+      "note": null,
+      "query_id": "q-003"
+    }
+  ],
+  "run_a": "run_a",
+  "run_b": "run_b"
+}

crates/kebab-eval/tests/fixtures/eval/run-1.json

@@ -0,0 +1,30 @@
+[
+  {
+    "error": null,
+    "first_hit": {
+      "chunk_id": "chunk000000000000000000000000000000",
+      "doc_id": "doc00000000000000000000000000000000",
+      "heading_path": [],
+      "score": 0.3429983854293823
+    },
+    "has_answer": false,
+    "hits_count": 1,
+    "mode": "lexical",
+    "query": "ownership",
+    "query_id": "q1"
+  },
+  {
+    "error": null,
+    "first_hit": {
+      "chunk_id": "chunk000000000000000000000000000002",
+      "doc_id": "doc00000000000000000000000000000002",
+      "heading_path": [],
+      "score": 0.3585492968559265
+    },
+    "has_answer": false,
+    "hits_count": 1,
+    "mode": "lexical",
+    "query": "heading",
+    "query_id": "q2"
+  }
+]