Update FG 2026 conference deadlines based on official website

- Updated Round 1 paper submission deadline: Oct 2 → Oct 6, 2025 (extended deadline)
- Updated Round 2 notification date: May 2 → April 2, 2026
- Updated camera-ready deadline: May 21 → April 21, 2026

All changes based on official FG 2026 website information.

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

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/data/conferences/fg.yml

@@ -10,8 +10,8 @@
     date: '2025-09-25 23:59:59'
     timezone: UTC-12
   - type: submission
-    label: Paper Submission (Round 1)
-    date: '2025-10-02 23:59:59'
+    label: Paper Submission (Round 1) - Extended
+    date: '2025-10-06 23:59:59'
     timezone: UTC-12
   - type: notification
     label: Notifications to authors (Round 1)
@@ -27,11 +27,11 @@
     timezone: UTC-12
   - type: notification
     label: Notifications to authors (Round 2)
-    date: '2026-05-02 23:59:59'
+    date: '2026-04-02 23:59:59'
     timezone: UTC-12
   - type: camera_ready
     label: Camera-ready (for all accepted papers)
-    date: '2026-05-21 23:59:59'
+    date: '2026-04-21 23:59:59'
     timezone: UTC-12
   timezone: GMT+02
   date: May 25-29, 2026