refactor(source-fs): drop kebab-parse-code dep — 9 tree-sitter grammars drag 제거

kebab-source-fs 가 kebab-parse-code 의 9 tree-sitter grammars 를 drag 했던 무거운 의존성 제거. 4 surface (code_lang_for_path / is_generated_file / is_oversized / BUILTIN_BLACKLIST) 만 사용하지만 dep 그래프에서 9 grammar 전체 link → kebab-source-fs::code_meta 로 이전 + kebab-parse-code 측 cleanup.

핵심 변경:
- kebab-source-fs::code_meta 신설: 4 surface 이전 (BUILTIN_BLACKLIST `pub` for frozen contract + 3 helper fn `pub(crate)`). lib.rs 의 `pub use code_meta::BUILTIN_BLACKLIST` 1 줄 추가 (Option A — 다른 mod surface 무근거 확장 0).
- callsite migration: media.rs (1) + walker.rs (2) + connector.rs (2) 모두 `kebab_source_fs::code_meta::*` 로 갱신.
- kebab-parse-code 측 cleanup: skip.rs 삭제 + lang.rs narrow edit (code_lang_for_path body + unit test 2 + Path import 삭제, module_path_for_* 보존) + lib.rs 헤더 doc rewrite (migration breadcrumb 포함).
- tests/{lang,skip}.rs 13 test 이동 — 12 unit (`src/code_meta.rs::tests`) + 1 integration (`tests/code_meta.rs` for BUILTIN_BLACKLIST frozen contract).
- design §8 graph: edge 제거 + p10-2 inline note. ARCHITECTURE.md 산문 1 줄 갱신. kebab-core::metadata.rs:36 stale dep reference 정정.

G1+G5: cargo tree -p kebab-source-fs | grep tree-sitter = 0 줄.
G2+G3: workspace test 회귀 0 + 13 test 1:1 이동.
G4: design §8 + ARCHITECTURE.md 갱신.

Wire 영향: 없음 (internal Rust crate-API surface 만, user-facing 0). Cargo workspace.version bump 불필요.

Refs:
- docs/superpowers/specs/2026-05-26-source-fs-dep-lightening-spec.md (v3, 4-round APPROVE)
- docs/superpowers/plans/2026-05-26-source-fs-dep-lightening-plan.md (v4, 4-round ACCEPT)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/kebab-source-fs/src/connector.rs

@@ -149,7 +149,7 @@ impl FsSourceConnector {
 
             // Generated-header sniff (config-gated).
             if self.skip_generated_header
-                && kebab_parse_code::is_generated_file(&abs_path).unwrap_or(false)
+                && crate::code_meta::is_generated_file(&abs_path).unwrap_or(false)
             {
                 fs_skips.skipped_generated =
                     fs_skips.skipped_generated.saturating_add(1);
@@ -166,7 +166,7 @@ impl FsSourceConnector {
             }
 
             // Size-cap check (byte or line limit).
-            if kebab_parse_code::is_oversized(
+            if crate::code_meta::is_oversized(
                 &abs_path,
                 self.max_file_bytes,
                 self.max_file_lines,