chore(deps): update renovate.json stability and add configMigration

[devin-ai-integration]

Why

Part of organization-wide standardization effort to apply consistent renovate.json configuration rules across all matsuri-tech repositories.

These changes implement the specified rules:

• Update minimumReleaseAge values less than 7 days to 7 days for more conservative dependency updates
• Add :configMigration to extends arrays that don't already contain it or config:best-practices

Link to Devin run: https://app.devin.ai/sessions/60a3d1f0b995416fbd6af9c725d7e4d7
Requested by: @hrdtbs

What

Updated renovate.json configuration:

• Added :configMigration: Added to extends array to enable automatic migration of deprecated Renovate configuration options
• Increased stability periods:
  • Minor updates: 3 days → 7 days
  • Patch updates: 1 day → 7 days

Review & Testing Checklist

• Verify that 7-day stability periods are appropriate for this repository's dependency update needs
• Confirm that the more conservative update schedule won't significantly delay important security patches
• Check that these changes match the standardized configuration applied across all matsuri-tech repositories
• Verify that adding :configMigration aligns with organization policy for Renovate configuration management

[devin-ai-integration]

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