fix(newos4): print the checkpoint name actually saved (auto)

Task 2 + ship of plan 2026-10-27_061724-newos4-checkpoint-name-mismatch.md.

module-system.js `checkpoint` read the clock a second time for the printed
name, so the name in "✅ Checkpoint created: <name>" differed from the name on
disk by >=1ms whenever no explicit name was given. It now prints the value
returned by fs.checkpoint(). try/catch and error strings unchanged.

Bundles rebuilt (rebuild-bundles.py); LATEST_VER in module-loader.js and all
three ?v= tags in main.html (core-bundle, module-loader, critical-ext-bundle)
bumped v4.6.101 -> v4.6.102.

Verification:
  $ node --check modules/core/module-system.js
  SYNTAX OK
  $ node --check modules/core/core-bundle.js
  BUNDLE SYNTAX OK
  $ node modules/test/test-vfs-checkpoint.js   (x5)
  test-vfs-checkpoint: 10 passed, 0 failed
  $ curl -s https://webx11.duckdns.org/spaces/newos4/main.html | grep -o 'core-bundle.js?v=[^"]*'
  core-bundle.js?v=v4.6.102
  $ python3 scripts/newos4-maintain.py
  PASS: version v4.6.102 x3 in main.html (expect 3) ... maintenance result: OK
  $ python3 scripts/newos4-skill-audit.py
  skill audit: 7/7 pass

4 files changed, 9 insertions, 11 deletions

diff --git a/main.html b/main.html
index 86c034c..b3d2c39 100644
--- a/main.html
+++ b/main.html
@@ -1349,13 +1349,13 @@
     </script>
 
     <!-- v4.5.63: A2A scratchpad fixes + agent-register arg fix -->
-<script src="modules/core/core-bundle.js?v=v4.6.101"></script>
+<script src="modules/core/core-bundle.js?v=v4.6.102"></script>
 
     <!-- Async dependency-ordered module loader now only initializes terminal and loads optional ext modules -->
-<script src="modules/core/module-loader.js?v=v4.6.101"></script>
+<script src="modules/core/module-loader.js?v=v4.6.102"></script>
 
     <!-- Critical ext bundle loads AFTER webx11 exists so registerModule calls work -->
-<script src="modules/ext/critical-ext-bundle.js?v=v4.6.101"></script>
+<script src="modules/ext/critical-ext-bundle.js?v=v4.6.102"></script>
 
 <script>
 // ═══ ONE TRUE VERSION SOURCE ═══
diff --git a/modules/core/core-bundle.js b/modules/core/core-bundle.js
index 32ff73b..cd510b7 100644
--- a/modules/core/core-bundle.js
+++ b/modules/core/core-bundle.js
@@ -968,7 +968,7 @@ class VirtualFileSystem {
             const toDelete = sorted.slice(0, all.length - 3);
             for (const old of toDelete) this.deleteCheckpoint(old);
         }
-        return true;
+        return name;
     }
     rollback(name) {
         const raw = this.fsReadJSON('/_snapshots/checkpoint-' + name + '.json');
@@ -6062,9 +6062,8 @@ Only output XML function calls for tool tasks. If no tool is needed, answer norm
                 this.commands['checkpoint'] = (args) => {
                     try {
                         const name = args[0] || '';
-                        this.terminal.fs.checkpoint(name);
-                        const displayName = name || new Date().toISOString();
-                        this.terminal.print('✅ Checkpoint created: ' + displayName, 'success');
+                        const created = this.terminal.fs.checkpoint(name);
+                        this.terminal.print('✅ Checkpoint created: ' + (created || name), 'success');
                     } catch (e) {
                         this.terminal.print('Checkpoint failed: ' + e.message, 'error');
                     }
diff --git a/modules/core/module-loader.js b/modules/core/module-loader.js
index 252c34b..b278f51 100644
--- a/modules/core/module-loader.js
+++ b/modules/core/module-loader.js
@@ -4,7 +4,7 @@
     // Core module bundle loaded synchronously in main.html.
     // This loader only handles version cache-busting, splash, terminal init, and optional ext modules.
 
-    const LATEST_VER = 'v4.6.101';
+    const LATEST_VER = 'v4.6.102';
     const CACHE = '?v=' + LATEST_VER;
     const stored = localStorage.getItem('webx11_cache_ver');
     if (stored !== LATEST_VER) {
diff --git a/modules/core/module-system.js b/modules/core/module-system.js
index b9b62a6..40b0861 100644
--- a/modules/core/module-system.js
+++ b/modules/core/module-system.js
@@ -479,9 +479,8 @@
                 this.commands['checkpoint'] = (args) => {
                     try {
                         const name = args[0] || '';
-                        this.terminal.fs.checkpoint(name);
-                        const displayName = name || new Date().toISOString();
-                        this.terminal.print('✅ Checkpoint created: ' + displayName, 'success');
+                        const created = this.terminal.fs.checkpoint(name);
+                        this.terminal.print('✅ Checkpoint created: ' + (created || name), 'success');
                     } catch (e) {
                         this.terminal.print('Checkpoint failed: ' + e.message, 'error');
                     }