v3.13 announcement (#2778)

* v3.13 announcement

* Update README.md

* Update lastShownAnnouncementId

* Tweak copy

Author: cte

.changeset/neat-dodos-serve.md

@@ -0,0 +1,5 @@
+---
+"roo-cline": patch
+---
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+Roo Code v3.13 announcement

README.md

@@ -49,13 +49,13 @@ Check out the [CHANGELOG](CHANGELOG.md) for detailed updates and fixes.
 
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-## 🎉 Roo Code 3.12 Released
+## 🎉 Roo Code 3.13 Released
 
-Roo Code 3.12 brings new features and improvements based on your feedback!
+Roo Code 3.13 brings new features and improvements based on your feedback!
 
-- **Grok Support** - Added the xAI provider and Grok reasoning effort options on OpenRouter.
-- **Diff Editing Improvements** - Per-profile configuration and better string normalization for fewer errors.
-- **Checkpoint Enhancements** - Faster and more reliable checkpoints.
+- **Gemini 2.5 Flash Thinking** - You can now use the thinking variant of Gemini 2.5 Flash and specify a thinking token budget.
+- **UI Improvements** - The task header, chat view, history preview, and welcome view have been visually upgraded.
+- **Bug Fixes** - More reliable diff edits & more.
 
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