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-parse-md/tests/frontmatter_snapshots.rs

@@ -0,0 +1,111 @@
+//! Snapshot tests pinning the §0 Q9 derive output for two fixtures.
+//!
+//! The baseline JSON next to each fixture is hand-authored / regenerated
+//! from a deterministic run. `BodyHints` timestamps are caller-provided
+//! and therefore stable; lingua autodetect over our fixtures is also
+//! stable for the language set we configured.
+
+use kebab_parse_md::{BodyHints, parse_frontmatter};
+use serde::Serialize;
+use serde_json::Value;
+use std::fs;
+use std::path::PathBuf;
+use time::macros::datetime;
+
+/// Stable view of the parser output suitable for JSON snapshotting.
+/// We deliberately exclude `FrontmatterSpan` byte offsets here too — they're
+/// fully determined by the input file and are exercised by unit tests; the
+/// snapshot focuses on the §0 Q9 derive contract.
+#[derive(Serialize)]
+struct Snapshot {
+    metadata: kebab_core::Metadata,
+    span_present: bool,
+    warnings: Vec<kebab_parse_types::Warning>,
+}
+
+fn fixtures_dir() -> PathBuf {
+    PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+        .join("..")
+        .join("..")
+        .join("fixtures")
+        .join("markdown")
+}
+
+fn pinned_hints() -> BodyHints {
+    BodyHints {
+        first_h1: None,
+        fs_ctime: datetime!(2024-01-01 00:00:00 UTC),
+        fs_mtime: datetime!(2024-01-02 00:00:00 UTC),
+        fallback_lang: None,
+    }
+}
+
+fn assert_snapshot(fixture: &str, baseline: &str) {
+    let dir = fixtures_dir();
+    let bytes = fs::read(dir.join(fixture)).expect("fixture readable");
+
+    let (meta, span, warns) = parse_frontmatter(&bytes, &pinned_hints()).unwrap();
+    let snap = Snapshot {
+        metadata: meta,
+        span_present: span.is_some(),
+        warnings: warns,
+    };
+    let actual: Value = serde_json::to_value(&snap).unwrap();
+
+    let expected_text =
+        fs::read_to_string(dir.join(baseline)).expect("snapshot baseline readable");
+    let expected: Value = serde_json::from_str(&expected_text).expect("baseline parses as json");
+
+    if actual != expected {
+        let actual_pretty = serde_json::to_string_pretty(&actual).unwrap();
+        panic!(
+            "snapshot drift for {fixture}\n\
+             --- expected ({baseline}) ---\n{expected_text}\n\
+             --- actual ---\n{actual_pretty}\n\
+             If the change is intentional, update {baseline}."
+        );
+    }
+}
+
+#[test]
+fn frontmatter_only_snapshot() {
+    assert_snapshot("frontmatter-only.md", "frontmatter-only.snapshot.json");
+}
+
+/// Run with `cargo test -p kb-parse-md --test frontmatter_snapshots emit_snapshots -- --ignored --nocapture`
+/// to regenerate the baseline JSON files from the current parser output.
+#[test]
+#[ignore]
+fn emit_snapshots() {
+    let dir = fixtures_dir();
+    for (fixture, baseline) in [
+        ("frontmatter-only.md", "frontmatter-only.snapshot.json"),
+        ("mixed-lang.md", "mixed-lang.snapshot.json"),
+    ] {
+        let bytes = fs::read(dir.join(fixture)).unwrap();
+        let (meta, span, warns) = parse_frontmatter(&bytes, &pinned_hints()).unwrap();
+        let snap = Snapshot {
+            metadata: meta,
+            span_present: span.is_some(),
+            warnings: warns,
+        };
+        let json = serde_json::to_string_pretty(&snap).unwrap();
+        fs::write(dir.join(baseline), format!("{json}\n")).unwrap();
+        eprintln!("wrote {}", dir.join(baseline).display());
+    }
+}
+
+#[test]
+fn mixed_lang_snapshot() {
+    assert_snapshot("mixed-lang.md", "mixed-lang.snapshot.json");
+}
+
+/// Determinism: parsing the same fixture twice in a row must give equal output.
+#[test]
+fn snapshot_is_deterministic_across_runs() {
+    let dir = fixtures_dir();
+    let bytes = fs::read(dir.join("frontmatter-only.md")).unwrap();
+    let (a, _, _) = parse_frontmatter(&bytes, &pinned_hints()).unwrap();
+    let (b, _, _) = parse_frontmatter(&bytes, &pinned_hints()).unwrap();
+    assert_eq!(serde_json::to_value(&a).unwrap(), serde_json::to_value(&b).unwrap());
+}