feat(spec): support tool aliases (#107)

closes #57

IRIS now automatically read and suggest internal configuration aliases
for Git (`.gitconfig`, `.git/config`) and Cargo (`.cargo/config.toml`)

- Added the `Provider` interface and extended registry for CLI tools
that define aliases
- Git: parse aliases via `git config --show-scope`, supporting raw
tab/space separation and scope differentiation
- Cargo: traverse the directory tree upwards to root to read the
`.cargo/config.toml` configuration
- 0ms hot-path caching: key caching is calculated entirely via `os.Stat`
mtime (no subprocess spawn) combined with a 2-second TTL window to
ensure 0ms latency when typing
- Lookup integration: display alias suggestions at the subcommand level
and automatically expand aliases as the user enters further arguments
(ignore shell pipeline commands starting with `!`)

root/suggestions_test.go

@@ -4,6 +4,7 @@ import (
 	"testing"
 
 	"github.com/versenilvis/iris/spec"
+	"github.com/versenilvis/iris/spec/alias"
 )
 
 func TestMergeResults(t *testing.T) {
@@ -48,6 +49,22 @@ func TestMergeResults(t *testing.T) {
 			t.Errorf("Expected promoted source 'ai', got %q", res[0].Source)
 		}
 	})
+
+	t.Run("Tool Alias Preserved When Matching Query", func(t *testing.T) {
+		alias.Register(&mockGitProvider{})
+		defer alias.Reset()
+		res := MergeResults("git co", "default")
+		foundCo := false
+		for _, r := range res {
+			if r.Cmd == "git co" {
+				foundCo = true
+				break
+			}
+		}
+		if !foundCo {
+			t.Errorf("expected 'git co' alias suggestion in results for query 'git co', got %v", res)
+		}
+	})
 }
 
 func TestPrevRecordedCommandState(t *testing.T) {