Put timestamp first in SPFxScaffoldLog JSONL output (#232)

## Description

Moves `timestamp` to be the first field in each serialized JSONL line in
`SPFxScaffoldLog`, making the log more human-readable when viewed line
by line (the timestamp is now immediately visible at the start of each
entry).

**Change in `append()`:**

```ts
// Before
const normalizedEvent = { ...event, timestamp: event.timestamp || new Date().toISOString() };

// After
const normalizedEvent = { timestamp: event.timestamp || new Date().toISOString(), ...event };
```

## How was this tested

- [ ] `rushx build` in `api/spfx-template-api/`

## Type of change

- [ ] Bug fix
- [x] New feature / enhancement
- [ ] Template change
- [ ] Docs / CI change only

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: iclanton

api/spfx-template-api/src/logging/SPFxScaffoldLog.ts

@@ -42,10 +42,11 @@ export class SPFxScaffoldLog {
    * it will be replaced with the current ISO 8601 timestamp.
    */
   public append(event: ISPFxScaffoldEventInput): void {
+    const { timestamp, ...rest } = event;
     const normalizedEvent: ISPFxScaffoldEvent = {
-      ...event,
-      timestamp: event.timestamp || new Date().toISOString()
-    } as ISPFxScaffoldEvent;
+      timestamp: timestamp || new Date().toISOString(),
+      ...rest
+    };
     this._events.push(normalizedEvent);
   }
 

common/changes/@microsoft/spfx-cli/main_2026-04-03-18-48.json

@@ -0,0 +1,11 @@
+{
+  "changes": [
+    {
+      "comment": "",
+      "type": "none",
+      "packageName": "@microsoft/spfx-cli"
+    }
+  ],
+  "packageName": "@microsoft/spfx-cli",
+  "email": "iclanton@users.noreply.github.com"
+}