feat: show scion version info on admin server config page

Add scion_version, scion_commit, and scion_build_time fields to the
ServerConfigResponse so the admin UI can display the server's build
information. The General tab now shows a "Scion Server Version" section
at the top with version, git commit, and build time.

Author: ptone

pkg/hub/admin_settings.go

@@ -21,12 +21,18 @@ import (
 	"path/filepath"
 
 	"github.com/GoogleCloudPlatform/scion/pkg/config"
+	"github.com/GoogleCloudPlatform/scion/pkg/version"
 	yamlv3 "gopkg.in/yaml.v3"
 )
 
 // ServerConfigResponse is the API representation of the server settings file.
 // It mirrors the on-disk settings.yaml structure, omitting sensitive fields.
 type ServerConfigResponse struct {
+	// Read-only server build info (not persisted in settings.yaml).
+	ScionVersion   string `json:"scion_version,omitempty"`
+	ScionCommit    string `json:"scion_commit,omitempty"`
+	ScionBuildTime string `json:"scion_build_time,omitempty"`
+
 	SchemaVersion        string                                `json:"schema_version"`
 	ActiveProfile        string                                `json:"active_profile,omitempty"`
 	DefaultTemplate      string                                `json:"default_template,omitempty"`
@@ -88,7 +94,12 @@ func (s *Server) handleGetServerConfig(w http.ResponseWriter) {
 	if err != nil {
 		if os.IsNotExist(err) {
 			// Return empty/default response if no settings file exists
-			writeJSON(w, http.StatusOK, ServerConfigResponse{SchemaVersion: "1"})
+			writeJSON(w, http.StatusOK, ServerConfigResponse{
+				ScionVersion:   version.Short(),
+				ScionCommit:    version.Commit,
+				ScionBuildTime: version.BuildTime,
+				SchemaVersion:  "1",
+			})
 			return
 		}
 		writeError(w, http.StatusInternalServerError, ErrCodeInternalError, "Failed to read settings file", nil)
@@ -103,6 +114,9 @@ func (s *Server) handleGetServerConfig(w http.ResponseWriter) {
 
 	// Mask sensitive fields before sending to the client
 	resp := ServerConfigResponse{
+		ScionVersion:         version.Short(),
+		ScionCommit:          version.Commit,
+		ScionBuildTime:       version.BuildTime,
 		SchemaVersion:        vs.SchemaVersion,
 		ActiveProfile:        vs.ActiveProfile,
 		DefaultTemplate:      vs.DefaultTemplate,

web/src/components/pages/admin-server-config.ts

@@ -167,6 +167,9 @@ interface V1RuntimeConfig {
 }
 
 interface ServerConfigResponse {
+  scion_version?: string;
+  scion_commit?: string;
+  scion_build_time?: string;
   schema_version: string;
   active_profile?: string;
   default_template?: string;
@@ -195,6 +198,11 @@ export class ScionPageAdminServerConfig extends LitElement {
   @state() private activeTab = 'general';
   @state() private reloadResult: ReloadResult | null = null;
 
+  // ── Read-only server build info ──
+  @state() private scionVersion = '';
+  @state() private scionCommit = '';
+  @state() private scionBuildTime = '';
+
   // ── Form state (mirrors settings.yaml) ──
 
   // General
@@ -372,6 +380,40 @@ export class ScionPageAdminServerConfig extends LitElement {
       color: var(--scion-text-muted, #64748b);
     }
 
+    .version-info {
+      display: flex;
+      flex-wrap: wrap;
+      gap: 1.5rem;
+    }
+
+    .version-item {
+      display: flex;
+      flex-direction: column;
+      gap: 0.125rem;
+    }
+
+    .version-label {
+      font-size: 0.75rem;
+      font-weight: 500;
+      color: var(--scion-text-muted, #64748b);
+      text-transform: uppercase;
+      letter-spacing: 0.025em;
+    }
+
+    .version-value {
+      font-size: 0.875rem;
+      color: var(--scion-text, #1e293b);
+    }
+
+    .version-value code {
+      font-family: var(--sl-font-mono, monospace);
+      font-size: 0.8125rem;
+      background: var(--scion-bg, #f8fafc);
+      padding: 0.125rem 0.375rem;
+      border-radius: 0.25rem;
+      border: 1px solid var(--scion-border, #e2e8f0);
+    }
+
     sl-input::part(base),
     sl-select::part(combobox),
     sl-textarea::part(base) {
@@ -474,6 +516,11 @@ export class ScionPageAdminServerConfig extends LitElement {
   }
 
   private populateForm(data: ServerConfigResponse): void {
+    // Server build info
+    this.scionVersion = data.scion_version || '';
+    this.scionCommit = data.scion_commit || '';
+    this.scionBuildTime = data.scion_build_time || '';
+
     // General
     this.activeProfile = data.active_profile || '';
     this.defaultTemplate = data.default_template || '';
@@ -817,8 +864,38 @@ export class ScionPageAdminServerConfig extends LitElement {
 
   // ── Tab renderers ──
 
+  private renderVersionInfo() {
+    if (!this.scionVersion && !this.scionCommit) return nothing;
+    return html`
+      <div class="section">
+        <h3 class="section-title">Scion Server Version</h3>
+        <div class="version-info">
+          ${this.scionVersion
+            ? html`<div class="version-item">
+                <span class="version-label">Version</span>
+                <span class="version-value">${this.scionVersion}</span>
+              </div>`
+            : nothing}
+          ${this.scionCommit
+            ? html`<div class="version-item">
+                <span class="version-label">Git Commit</span>
+                <span class="version-value"><code>${this.scionCommit}</code></span>
+              </div>`
+            : nothing}
+          ${this.scionBuildTime
+            ? html`<div class="version-item">
+                <span class="version-label">Build Time</span>
+                <span class="version-value">${this.scionBuildTime}</span>
+              </div>`
+            : nothing}
+        </div>
+      </div>
+    `;
+  }
+
   private renderGeneralTab() {
     return html`
+      ${this.renderVersionInfo()}
       <div class="section">
         <h3 class="section-title">General Settings</h3>
         <div class="form-grid">