chore: add changeset for AI assistants support and validation fixes (#227)

* fix: manually merge and archive four completed OpenSpec changes

Merged and archived four concurrent changes that modified the same specs:
- add-cline-support: Added Cline AI tool configuration
- add-crush-support: Added Crush AI tool configuration
- add-factory-slash-commands: Added Factory Droid slash commands
- add-archive-command-arguments: Added archive command argument support

Changes to cli-init/spec.md:
- Added Cline and CodeBuddy Code configuration scenarios
- Added slash command scenarios for CodeBuddy Code, Cline, Crush, Factory Droid

Changes to cli-update/spec.md:
- Added update scenarios for CodeBuddy Code, Cline, Crush, Factory Droid
- Added Archive Command Argument Support requirement
- Modified OpenCode scenario to support $ARGUMENTS placeholder

This required manual intervention to prevent data loss from OpenSpec's
requirement-level replacement during archiving. The archive operations
initially overwrote scenarios from earlier changes, requiring restoration
of all missing content to preserve complete spec state.

All four changes successfully archived to openspec/changes/archive/.

* Add changeset for AI assistants support and validation fixes

.changeset/ai-assistants-and-fixes.md

@@ -0,0 +1,24 @@
+---
+"@fission-ai/openspec": minor
+---
+
+Add support for multiple AI assistants and improve validation
+
+This release adds support for several new AI coding assistants:
+- CodeBuddy Code - AI-powered coding assistant
+- CodeRabbit - AI code review assistant
+- Cline - Claude-powered CLI assistant
+- Crush AI - AI assistant platform
+- Auggie (Augment CLI) - Code augmentation tool
+
+New features:
+- Archive slash command now supports arguments for more flexible workflows
+
+Bug fixes:
+- Delta spec validation now handles case-insensitive headers and properly detects empty sections
+- Archive validation now correctly honors --no-validate flag and ignores metadata
+
+Documentation improvements:
+- Added VS Code dev container configuration for easier development setup
+- Updated AGENTS.md with explicit change-id notation
+- Enhanced slash commands documentation with restart notes