[FEATURE] support python 3.14

Use Case / Problem

In this comment: https://github.com/microsoft/fabric-cli/issues/89#issuecomment-3908063521 python 3.14 was said to be unavailable because a dependency (msal) did not support it.

msal added python 3.14 support ~3 months ago: https://github.com/AzureAD/microsoft-authentication-library-for-python/releases/tag/1.35.0

Proposed Solution

I think the python version upper bound should be removed entirely. I don't think it is good practice to include that - especially when the reasoning is due to dependencies.

Alternatives Considered

No response

Impact Assessment

• This would help me personally
• This would help my team/organization
• This would help the broader fabric-cli community
• This aligns with Microsoft Fabric roadmap items

Implementation Attestation

• I understand this feature should maintain backward compatibility with existing commands
• I confirm this feature request does not introduce performance regressions for existing workflows
• I acknowledge that new features must follow fabric-cli's established patterns and conventions

Implementation Notes

No response