feat(p10-1a-1): kebab-parse-code crate (lang + repo + skip)

Tasks 5-8: new `kebab-parse-code` crate with three infrastructure modules
for the code ingest framework. Ships lang.rs (extension→language identifier
mapping), repo.rs (.git walk-up via gix 0.70 for RepoMeta), and skip.rs
(BUILTIN_BLACKLIST, is_generated_file, is_oversized). 14 integration tests
across three test files, all passing; clippy -D warnings clean.

Note: gix pinned to 0.70 (not 0.83 as originally suggested) because 0.83
fails to compile against Rust 1.94.1 due to non-exhaustive match patterns
in gix-hash. 0.70 resolves cleanly and has identical head_name/head_id API.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Cargo.toml

@@ -23,6 +23,7 @@ members = [
     "crates/kebab-parse-pdf",
     "crates/kebab-tui",
     "crates/kebab-mcp",
+    "crates/kebab-parse-code",
 ]
 
 [workspace.package]
@@ -81,6 +82,10 @@ rmcp         = { version = "1.6", default-features = false, features = ["server"
 # sync via reqwest::blocking — wiremock is dev-only there).
 wiremock     = "0.6"
 base64       = "0.22"
+# Pure-Rust git library for repo metadata detection (kebab-parse-code).
+# No `git` binary required. Default features include thread-safety + most
+# object-reading capabilities needed for HEAD name + commit SHA queries.
+gix          = { version = "0.70", default-features = false, features = ["revision"] }
 
 # Disk-footprint trim for dev / test builds. Codegen, opt-level, and
 # behavior are unchanged — only DWARF debug info is reduced (line