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-chunk/Cargo.toml

@@ -0,0 +1,26 @@
+[package]
+name = "kebab-chunk"
+version       = { workspace = true }
+edition       = { workspace = true }
+rust-version  = { workspace = true }
+license       = { workspace = true }
+repository    = { workspace = true }
+description   = "Chunkers that turn kb-core::CanonicalDocument into kb-core::Chunk batches (§3.5, §4.2, §7.2)"
+
+[dependencies]
+kebab-core = { path = "../kebab-core" }
+serde_json_canonicalizer   = "0.3"
+blake3                     = { workspace = true }
+anyhow                     = { workspace = true }
+tracing                    = { workspace = true }
+
+[dev-dependencies]
+# kb-parse-md / kb-normalize are dev-only — used by the snapshot integration
+# test to build a CanonicalDocument from a fixture Markdown file. Forbidden as
+# regular deps per design §8 (chunker consumes CanonicalDocument from kb-core
+# only); `cargo tree -p kb-chunk --depth 1` (default scope, excludes dev-deps)
+# confirms this.
+kebab-parse-md = { path = "../kebab-parse-md" }
+kebab-normalize = { path = "../kebab-normalize" }
+serde_json      = { workspace = true }
+time            = { workspace = true }