refactor(rename): kb → kebab — binary, env vars, XDG paths, file renames

두 번째 commit. 사용자 facing surface (CLI binary, env vars, XDG paths)
+ 코드 안 single-letter token (`KB_`, `kb.sqlite`, `/kb/`, tracing
target) 일괄 rename. 그리고 3 개 file rename:

- 디자인 doc `2026-04-27-kb-final-form-design.md` →
  `2026-04-27-kebab-final-form-design.md`
- 최초 보고서 `kb_local_rust_report.md` → `kebab_local_rust_report.md`
- workspace ignore `.kbignore` → `.kebabignore`

## 변경

- `crates/kebab-cli/Cargo.toml`: `[[bin]] name = "kb"` → `"kebab"`.
- `crates/kebab-cli/src/main.rs`: `#[command(name = "kb", …)]` →
  `name = "kebab"`.
- 모든 `KB_*` env var (코드 + doc + 테스트) → `KEBAB_*`. apply_env
  prefix 매칭 + 30+ 개 setting 키 모두.
- XDG paths: `~/.config/kb` / `~/.local/share/kb` / `~/.cache/kb` /
  `~/.local/state/kb` → `~/.config/kebab` 등. config defaults +
  expand_path tests + paths.rs 의 hardcode 모두.
- SQLite filename: `kb.sqlite` → `kebab.sqlite` (`SQLITE_FILE` const
  + 테스트 hardcode 모두).
- tracing target: `target: "kb-*"` → `"kebab-*"` (10+ 곳).
- snapshot fixture: `.kbignore` → `.kebabignore` (`fixtures/source-fs/
  tree-1.snapshot.json` 갱신).

## 검증

- `cargo test --workspace -j 1` clean (linker OOM 회피 위해 직렬).
- `cargo clippy --workspace --all-targets -- -D warnings` clean.

다음 commit 에서 docs sweep.

🤖 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/src/lib.rs

@@ -20,7 +20,7 @@
 //! serializes vector ops, and current-thread saves the two worker
 //! threads a multi-thread runtime spawns by default.
 //!
-//! See `docs/superpowers/specs/2026-04-27-kb-final-form-design.md`
+//! See `docs/superpowers/specs/2026-04-27-kebab-final-form-design.md`
 //! §5.6 (embedding_records DDL), §6.3 (lancedb table naming),
 //! §7.2 (VectorStore), §9 (versioning).
 

crates/kebab-store-vector/src/store.rs

@@ -111,7 +111,7 @@ impl LanceVectorStore {
             })?;
 
         tracing::debug!(
-            target: "kb-store-vector",
+            target: "kebab-store-vector",
             vector_dir = %vector_dir.display(),
             "opened LanceVectorStore"
         );
@@ -141,7 +141,7 @@ impl LanceVectorStore {
                     .await
                     .context("create_empty_table")?;
                 tracing::info!(
-                    target: "kb-store-vector",
+                    target: "kebab-store-vector",
                     table = table_name,
                     dim,
                     "created Lance table"
@@ -275,7 +275,7 @@ impl VectorStore for LanceVectorStore {
             .context("phase 3: mark embedding_records committed")?;
 
         tracing::info!(
-            target: "kb-store-vector",
+            target: "kebab-store-vector",
             table = %table_name,
             rows = recs.len(),
             "upsert committed"
@@ -306,7 +306,7 @@ impl VectorStore for LanceVectorStore {
             Some(name) => name,
             None => {
                 tracing::debug!(
-                    target: "kb-store-vector",
+                    target: "kebab-store-vector",
                     dim,
                     "search: no Lance table matches query dim — returning empty"
                 );
@@ -477,7 +477,7 @@ fn decode_lance_hits(batches: &[RecordBatch]) -> Result<Vec<LanceCandidate>> {
 fn score_from_distance(distance: f32) -> f32 {
     if distance.is_nan() {
         tracing::warn!(
-            target: "kb-store-vector",
+            target: "kebab-store-vector",
             "NaN cosine distance from Lance — coercing to score 0"
         );
         return 0.0;
@@ -515,7 +515,7 @@ async fn find_matching_table(
             }
             Err(e) => {
                 tracing::warn!(
-                    target: "kb-store-vector",
+                    target: "kebab-store-vector",
                     table = %name,
                     error = %e,
                     "search: skipped unopenable table"

crates/kebab-store-vector/tests/snapshot.rs

@@ -73,7 +73,7 @@ fn vector_hits_snapshot_run_1() {
         .join("vector")
         .join("run-1.json");
 
-    if std::env::var_os("KB_UPDATE_SNAPSHOTS").is_some() {
+    if std::env::var_os("KEBAB_UPDATE_SNAPSHOTS").is_some() {
         std::fs::create_dir_all(fixture.parent().unwrap()).unwrap();
         std::fs::write(&fixture, serde_json::to_string_pretty(&actual).unwrap())
             .unwrap();
@@ -83,7 +83,7 @@ fn vector_hits_snapshot_run_1() {
     let expected: serde_json::Value =
         serde_json::from_str(&std::fs::read_to_string(&fixture).unwrap_or_else(
             |_| panic!(
-                "missing snapshot fixture at {}; run with KB_UPDATE_SNAPSHOTS=1 to create",
+                "missing snapshot fixture at {}; run with KEBAB_UPDATE_SNAPSHOTS=1 to create",
                 fixture.display()
             ),
         ))
@@ -97,14 +97,14 @@ fn vector_hits_snapshot_run_1() {
         panic!(
             "snapshot fixture is a placeholder — regenerate on AVX hardware then commit. \
              Path: {}. To regenerate: \
-             `KB_UPDATE_SNAPSHOTS=1 cargo test -p kb-store-vector -- --ignored snapshot`.",
+             `KEBAB_UPDATE_SNAPSHOTS=1 cargo test -p kb-store-vector -- --ignored snapshot`.",
             fixture.display()
         );
     }
 
     assert_eq!(
         actual, expected,
-        "snapshot drift; rerun with KB_UPDATE_SNAPSHOTS=1 to regenerate"
+        "snapshot drift; rerun with KEBAB_UPDATE_SNAPSHOTS=1 to regenerate"
     );
 
     // Independent guard: scores must be non-increasing.