feat: adding support for AIDLC v2 alpha

[leandrodamascena]

Summary

Add v2 (alpha) references to the README and issue templates so users know v2 exists and can report issues against the correct version.

Changes

• Added a notice banner at the top of README.md linking to the v2 branch
• Added a "Version" dropdown (v1 current / v2 alpha) to bug report, feature request, and documentation issue templates
• Kept the release/commit hash field in bug reports for detailed version tracking

User experience

Before: No mention of v2 anywhere. Users could only file issues against v1 with no version distinction.

After: Users see a notice that v2 (alpha) is available. When filing issues, they select which version they're using.

Checklist

• I have reviewed the contributing guidelines
• I have performed a self-review of this change
• Changes have been tested
• Changes are documented

Acknowledgment

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of the project license.

[leandrodamascena]

Hey @harmjeff @scottschreckengaust can I have your approval here?