chore: add changeset for new features and improvements (Fission-AI#326)

* Add changeset for new features and improvements

* Update .changeset/new-features-and-improvements.md

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

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Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

Author: TabishB

.changeset/new-features-and-improvements.md

@@ -0,0 +1,12 @@
+---
+"@fission-ai/openspec": minor
+---
+
+Add new AI tool integrations and enhancements:
+
+- **feat(iflow-cli)**: Add iFlow-cli integration with slash command support and documentation
+- **feat(init)**: Add IDE restart instruction after init to inform users about slash command availability
+**feat(antigravity)**: Add Antigravity slash command support
+- **fix**: Generate TOML commands for Qwen Code (fixes #293)
+- Clarify scaffold proposal documentation and enhance proposal guidelines
+- Update proposal guidelines to emphasize design-first approach before implementation