feat(web,server): expose server version and commit hash in Profile page

Add version and commit_hash fields to the /ping endpoint response,
sourced from the existing internal/version package (ldflags or
Go build info). The frontend capabilities store reads these values
and displays them as badges at the bottom of the Profile page.

internal/handlers/ping.go

@@ -7,12 +7,15 @@ import (
 	"github.com/labstack/echo/v4"
 
 	"github.com/memohai/memoh/internal/boot"
+	"github.com/memohai/memoh/internal/version"
 )
 
 type PingResponse struct {
 	Status            string `json:"status"`
 	ContainerBackend  string `json:"container_backend"`
 	SnapshotSupported bool   `json:"snapshot_supported"`
+	Version           string `json:"version"`
+	CommitHash        string `json:"commit_hash"`
 }
 
 type PingHandler struct {
@@ -42,6 +45,8 @@ func (h *PingHandler) Ping(c echo.Context) error {
 		Status:            "ok",
 		ContainerBackend:  h.runtime.ContainerBackend,
 		SnapshotSupported: h.runtime.ContainerBackend != "apple",
+		Version:           version.Version,
+		CommitHash:        version.ShortCommitHash(),
 	})
 }
 

internal/version/version.go

@@ -17,8 +17,9 @@ var (
 	BuildTime = ""
 )
 
-// GetInfo returns a formatted version string including the version and commit hash.
-func GetInfo() string {
+// EnsureBuildInfo populates CommitHash and BuildTime from Go build info
+// when they were not set via ldflags.
+func EnsureBuildInfo() {
 	if CommitHash == "" {
 		if info, ok := debug.ReadBuildInfo(); ok {
 			for _, setting := range info.Settings {
@@ -31,15 +32,23 @@ func GetInfo() string {
 			}
 		}
 	}
+}
 
+// ShortCommitHash returns the first 7 characters of the commit hash.
+func ShortCommitHash() string {
+	EnsureBuildInfo()
+	if len(CommitHash) > 7 {
+		return CommitHash[:7]
+	}
+	return CommitHash
+}
+
+// GetInfo returns a formatted version string including the version and commit hash.
+func GetInfo() string {
+	EnsureBuildInfo()
 	res := Version
-	if CommitHash != "" {
-		// Only use the first 7 characters of the commit hash if it's long
-		shortHash := CommitHash
-		if len(shortHash) > 7 {
-			shortHash = shortHash[:7]
-		}
-		res += fmt.Sprintf(" (%s)", shortHash)
+	if h := ShortCommitHash(); h != "" {
+		res += fmt.Sprintf(" (%s)", h)
 	}
 	return res
 }