chore: migrate from git command to gix (#16)

Reviewed-on: https://git.reya.su/reya/signed/pulls/16

Cargo.lock

@@ -2524,6 +2524,7 @@ dependencies = [
  "gix-credentials",
  "gix-date",
  "gix-diff",
+ "gix-dir",
  "gix-discover",
  "gix-error",
  "gix-features",
@@ -2551,6 +2552,7 @@ dependencies = [
  "gix-revwalk",
  "gix-sec",
  "gix-shallow",
+ "gix-status",
  "gix-submodule",
  "gix-tempfile",
  "gix-trace",
@@ -2710,13 +2712,16 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1b1689ff5ddeee4acfb2a43e875a1072a76d208624b15a9065c938b39cb0da2a"
 dependencies = [
  "bstr",
+ "gix-attributes",
  "gix-command",
  "gix-filter",
  "gix-fs",
  "gix-hash",
  "gix-imara-diff",
+ "gix-index",
  "gix-object",
  "gix-path",
+ "gix-pathspec",
  "gix-tempfile",
  "gix-trace",
  "gix-traverse",
@@ -2724,6 +2729,26 @@ dependencies = [
  "thiserror 2.0.20",
 ]
 
+[[package]]
+name = "gix-dir"
+version = "0.29.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8342d5eb0ea054ed6ef807e628e38f06dd51eceeec9529767d8b23e33eff9c09"
+dependencies = [
+ "bstr",
+ "gix-discover",
+ "gix-fs",
+ "gix-ignore",
+ "gix-index",
+ "gix-object",
+ "gix-path",
+ "gix-pathspec",
+ "gix-trace",
+ "gix-utils",
+ "gix-worktree",
+ "thiserror 2.0.20",
+]
+
 [[package]]
 name = "gix-discover"
 version = "0.55.0"
@@ -3182,6 +3207,31 @@ dependencies = [
  "thiserror 2.0.20",
 ]
 
+[[package]]
+name = "gix-status"
+version = "0.34.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1401d871c01d82add5a9f654439b00722d0c632b332cd2cb63193f94327c8458"
+dependencies = [
+ "bstr",
+ "filetime",
+ "gix-diff",
+ "gix-dir",
+ "gix-features",
+ "gix-filter",
+ "gix-fs",
+ "gix-hash",
+ "gix-index",
+ "gix-object",
+ "gix-path",
+ "gix-pathspec",
+ "gix-worktree",
+ "hashbrown 0.16.1",
+ "portable-atomic",
+ "thiserror 2.0.20",
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "gix-submodule"
 version = "0.34.0"
@@ -7909,6 +7959,8 @@ version = "0.1.0-alpha"
 dependencies = [
  "anyhow",
  "gix",
+ "gix-worktree",
+ "gix-worktree-state",
  "nostr",
  "signed_core",
  "tempfile",