Add version tags alongside commit hashes in output

- tools.json now has both "version" (tag) and "hash" (commit) fields
- Output format: toolname@version [hash] (in duration)
- Update tool fetches and stores both version and hash
- Fix .gitignore to not exclude cmd/update directory

cmd/update/main.go

@@ -17,6 +17,7 @@ type Tool struct {
 	Name    string `json:"name"`
 	Package string `json:"package"`
 	Version string `json:"version"`
+	Hash    string `json:"hash"`
 	Date    string `json:"date"`
 }
 
@@ -85,11 +86,15 @@ func main() {
 			failed++
 		} else {
 			updatedTools[r.idx] = r.updated
-			if r.tool.Version != r.updated.Version {
-				fmt.Printf("↑ %s: %s -> %s\n", r.tool.Name, r.tool.Version, r.updated.Version)
+			oldHash := r.tool.Hash
+			if oldHash == "" {
+				oldHash = r.tool.Version // migration from old format
+			}
+			if oldHash != r.updated.Hash {
+				fmt.Printf("↑ %s: %s [%s] -> %s [%s]\n", r.tool.Name, r.tool.Version, shortHash(oldHash), r.updated.Version, r.updated.Hash[:12])
 				changed++
 			} else {
-				fmt.Printf("✓ %s: %s (unchanged)\n", r.tool.Name, r.tool.Version)
+				fmt.Printf("✓ %s: %s [%s] (unchanged)\n", r.tool.Name, r.updated.Version, r.updated.Hash[:12])
 			}
 			succeeded++
 		}
@@ -226,7 +231,8 @@ func fetchLatestVersion(tool Tool) (Tool, error) {
 		return Tool{
 			Name:    tool.Name,
 			Package: tool.Package,
-			Version: fullHash,
+			Version: info.Version,
+			Hash:    fullHash,
 			Date:    date,
 		}, nil
 	}
@@ -243,7 +249,8 @@ func fetchLatestVersion(tool Tool) (Tool, error) {
 	return Tool{
 		Name:    tool.Name,
 		Package: tool.Package,
-		Version: hash,
+		Version: info.Version,
+		Hash:    hash,
 		Date:    date,
 	}, nil
 }
@@ -294,3 +301,10 @@ type result struct {
 	updated Tool
 	err     error
 }
+
+func shortHash(h string) string {
+	if len(h) >= 12 {
+		return h[:12]
+	}
+	return h
+}