enhance: improve hashFiles coercion and log grouping (#1394)

- Fix `hashFiles()` argument conversion for numbers, booleans, and null to match GitHub expression semantics.
- Fix rendering of mixed-case, indented, and prefixed legacy group commands while preserving recognized prefixes and escaping.

Reviewed-on: https://gitea.com/gitea/runner/pulls/1394
Reviewed-by: bircni <[email protected]>
Co-authored-by: silverwind <[email protected]>

act/runner/expression.go

@@ -136,7 +136,7 @@ func getHashFilesFunction(ctx context.Context, rc *RunContext) func(v []reflect.
 			followSymlink := false
 
 			for i, p := range v {
-				s := p.String()
+				s := exprparser.CoerceToString(p)
 				if i == 0 && strings.HasPrefix(s, "--") {
 					if strings.EqualFold(s, "--follow-symbolic-links") {
 						followSymlink = true