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-store-vector/tests/fixtures/vector/run-1.json

@@ -0,0 +1,34 @@
+[
+  {
+    "chunk_id": "00000000000000000000000000001100",
+    "payload": {
+      "doc_id": "0000000000000000000000000000d0c0",
+      "heading_path": [
+        "A"
+      ],
+      "text": "alpha"
+    },
+    "score_in_unit_interval": true
+  },
+  {
+    "chunk_id": "00000000000000000000000000001101",
+    "payload": {
+      "doc_id": "0000000000000000000000000000d0c1",
+      "heading_path": [
+        "A",
+        "B"
+      ],
+      "text": "beta"
+    },
+    "score_in_unit_interval": true
+  },
+  {
+    "chunk_id": "00000000000000000000000000001103",
+    "payload": {
+      "doc_id": "0000000000000000000000000000d0c3",
+      "heading_path": [],
+      "text": "delta"
+    },
+    "score_in_unit_interval": true
+  }
+]