Add activity stubs to generic template

[fyzanshaik-atlan]

Changelog

• Added stub implementations for get_workflow_args and extract_and_transform_metadata activities in template's activities.py
• Fixes template mismatch where workflow.py referenced activities that weren't defined
• Developers now get a working template out of the box instead of immediate type errors

Additional context (e.g. screenshots, logs, links)

• Discovered while following Build Custom App tutorial
• Template's workflow.py calls activities_instance.get_workflow_args but activities.py had no such method defined
• This caused type errors and confusion for developers starting with the template

Checklist

• Additional tests added
• All CI checks passed
• Relevant documentation updated

[github-actions]

📦 Trivy Vulnerability Scan Results

Schema Version	Created At	Artifact	Type
2	2026-01-29T19:05:22.700624972Z	.	filesystem

Report Summary

Target	Type	Vulnerabilities	.	filesystem	✅ None found

Scan Result Details

✅ No vulnerabilities found during the scan for ..

[github-actions]

📦 Trivy Secret Scan Results

Schema Version	Created At	Artifact	Type
2	2026-01-29T19:05:40.342905741Z	.	filesystem

Report Summary

Target	Type	Secrets	.	filesystem	✅ None found

Scan Result Details

✅ No secrets found during the scan for ..