fix: align model capabilities schema with OpenCode v2 root properties…

[ganimalqudhaifi]

Based on the dev branch, added root properties (reasoning, attachment, tool_call, modalities) for OpenCode v2 compatibility.

Summary by CodeRabbit

• Bug Fixes
  • Improved compatibility with OpenCode v2 model caching.
  • Preserved model-specific settings, including reasoning, attachments, tool calls, temperature, modalities, and input/output capabilities.
  • Prevented model configuration changes from unintentionally affecting shared defaults.

[ganimalqudhaifi]

you can check this different with 'opencode models google-agy --verbose'

[anthonyhaussman]

The static defaults (modelDetails) are being spread after the custom configurations (existing) for modalities and capabilities. This causes the static defaults to silently overwrite any custom model configurations provided by the user/provider.

Suggested change

	temperature: (existing as any).temperature ?? (modelDetails as any).temperature,
	modalities: {
	...((existing as any).modalities || {}),
	...((modelDetails as any).modalities || {})
	},
	capabilities: {
	...(existing.capabilities || {}),
	...(modelDetails.capabilities || {}),
	input: {
	...(existing.capabilities?.input || {}),
	...(modelDetails.capabilities?.input || {})
	},
	output: {
	...(existing.capabilities?.output || {}),
	...(modelDetails.capabilities?.output || {})
	}
	modalities: {
	...((modelDetails as any).modalities || {}),
	...((existing as any).modalities || {})
	},
	capabilities: {
	...(modelDetails.capabilities || {}),
	...(existing.capabilities || {}),
	input: {
	...(modelDetails.capabilities?.input || {}),
	...(existing.capabilities?.input || {})
	},
	output: {
	...(modelDetails.capabilities?.output || {}),
	...(existing.capabilities?.output || {})
	}
	}