fix: use claude_args instead of invalid model input for Opus 4.6

`model` is not a valid input for claude-code-action@v1. The correct
way to set the model is via `claude_args: '--model claude-opus-4-6'`.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: kevin1chun

.github/workflows/claude-code-review.yml

@@ -36,7 +36,7 @@ jobs:
         uses: anthropics/claude-code-action@v1
         with:
           claude_code_oauth_token: ${{ secrets.CLAUDE_CODE_OAUTH_TOKEN }}
-          model: 'claude-opus-4-6'
+          claude_args: '--model claude-opus-4-6'
           plugin_marketplaces: 'https://github.com/anthropics/claude-code.git'
           plugins: 'code-review@claude-code-plugins'
           prompt: '/code-review:code-review ${{ github.repository }}/pull/${{ github.event.pull_request.number }}'

.github/workflows/claude.yml

@@ -35,7 +35,7 @@ jobs:
         uses: anthropics/claude-code-action@v1
         with:
           claude_code_oauth_token: ${{ secrets.CLAUDE_CODE_OAUTH_TOKEN }}
-          model: 'claude-opus-4-6'
+          claude_args: '--model claude-opus-4-6'
 
           # This is an optional setting that allows Claude to read CI results on PRs
           additional_permissions: |