test(tools): add unit tests for error handling functions

* Implement tests for error functions like errRequiredField, errInvalidField, and errEntityNotFound.
* Ensure proper metadata is returned for various error scenarios.
* Validate error handling in CRM, Files, and other tools.
* Introduce tests for parsing stored file IDs and UUIDs.
* Enhance coverage for helper functions related to project resolution and session management.

internal/buildinfo/buildinfo.go

@@ -0,0 +1,41 @@
+package buildinfo
+
+import "strings"
+
+var (
+	Version   = "dev"
+	TagName   = "dev"
+	Commit    = "unknown"
+	BuildDate = "unknown"
+)
+
+type Info struct {
+	Version   string `json:"version"`
+	TagName   string `json:"tag_name"`
+	Commit    string `json:"commit"`
+	BuildDate string `json:"build_date"`
+}
+
+func Current() Info {
+	info := Info{
+		Version:   strings.TrimSpace(Version),
+		TagName:   strings.TrimSpace(TagName),
+		Commit:    strings.TrimSpace(Commit),
+		BuildDate: strings.TrimSpace(BuildDate),
+	}
+
+	if info.Version == "" {
+		info.Version = "dev"
+	}
+	if info.TagName == "" {
+		info.TagName = info.Version
+	}
+	if info.Commit == "" {
+		info.Commit = "unknown"
+	}
+	if info.BuildDate == "" {
+		info.BuildDate = "unknown"
+	}
+
+	return info
+}

internal/buildinfo/buildinfo_test.go

@@ -0,0 +1,32 @@
+package buildinfo
+
+import "testing"
+
+func TestCurrentAppliesFallbacks(t *testing.T) {
+	originalVersion, originalTagName, originalCommit, originalBuildDate := Version, TagName, Commit, BuildDate
+	t.Cleanup(func() {
+		Version = originalVersion
+		TagName = originalTagName
+		Commit = originalCommit
+		BuildDate = originalBuildDate
+	})
+
+	Version = ""
+	TagName = ""
+	Commit = ""
+	BuildDate = ""
+
+	info := Current()
+	if info.Version != "dev" {
+		t.Fatalf("version = %q, want %q", info.Version, "dev")
+	}
+	if info.TagName != "dev" {
+		t.Fatalf("tag_name = %q, want %q", info.TagName, "dev")
+	}
+	if info.Commit != "unknown" {
+		t.Fatalf("commit = %q, want %q", info.Commit, "unknown")
+	}
+	if info.BuildDate != "unknown" {
+		t.Fatalf("build_date = %q, want %q", info.BuildDate, "unknown")
+	}
+}