Enable parallel tool calls by default

[daniel-lxs]

This PR removes the multipleNativeToolCalls experiment and enables parallel tool calling by default across the entire codebase.

Changes

Core Updates

• Task.ts: Changed all parallelToolCalls defaults from false to true (4 locations)
• presentAssistantMessage.ts: Removed didAlreadyUseTool enforcement logic
• converters.ts: Updated to enable parallel by default
• index.ts: Updated JSDoc to reflect new default
• system.ts: Removed experiments parameter from tool sections

API Provider Updates (13 providers)

Updated all providers to default parallelToolCalls to true:

• openai-native, openai, openai-codex
• cerebras, qwen-code, lm-studio
• unbound, vercel-ai-gateway, zai
• deepinfra, xai, deepseek
• base-openai-compatible-provider

Test Updates

• Updated 10+ test files to expect parallel tool calling by default
• Updated Anthropic converter tests
• Removed obsolete didAlreadyUseTool tests
• Updated 9 prompt snapshot files

Cleanup

• Removed MULTIPLE_NATIVE_TOOL_CALLS from all 17 i18n locale files
• Removed multipleNativeToolCalls from experiments test file

Impact

• Models can now call multiple tools in a single response by default
• Improves efficiency by reducing back-and-forth
• Maintains backward compatibility (can be disabled with parallelToolCalls: false)

[roomote]

Rooviewer   See task on Roo Cloud

PR Review Summary

Review Status: ✅ APPROVED

This PR removes the multipleNativeToolCalls experiment and enables parallel tool calling by default across all API providers.

Key Changes Verified

1. Experiment Removal - Complete and consistent removal from types and config
2. Provider Updates - All 13+ providers default parallel_tool_calls: true
3. Task.ts - 4 locations now pass parallelToolCalls: true explicitly
4. Anthropic Converter - Correctly handles the new default
5. Tool Use Guidelines - Updated to encourage parallel tool use
6. presentAssistantMessage.ts - Removed didAlreadyUseTool enforcement logic
7. i18n Cleanup - All 17 locale files cleaned up
8. Tests - All tests pass with updated expectations

Issues Found

None - This is a clean, well-structured PR.

Previous reviews

• 291e195: Review #1

_{Mention @roomote in a comment to request specific changes to this pull request or fix all unresolved issues.}

[roomote]

Thoroughly reviewed all changes. The PR cleanly removes the multipleNativeToolCalls experiment and enables parallel tool calls by default across all 13+ API providers. All tests pass. Well-structured implementation with complete cleanup of i18n files and experiment-related code.