Enable Python 3.14 runtime support for serverless Functions

[kwiatekus]

Description

The Python 3.14 runtime image and server implementation have already been introduced in #2083 under components/runtimes/python314/. The runtime is based on Python 3.14.3 (Alpine), includes all required dependencies (Flask, gevent, OpenTelemetry, CloudEvents), and supports both FIPS and non-FIPS base images. However, it has not yet been wired into the serverless module as a supported Function runtime — it is not listed in the Function CR API, the controller configuration, the Busola UI extension, or the documentation.

This issue tracks all work required to make python314 a selectable runtime for end users.

Reasons

Python 3.14 is the latest stable release and provides performance improvements and language features over 3.12. Offering it keeps the Serverless module current with the Python ecosystem and gives users a supported upgrade path from python312.

Acceptance Criteria

• python314 is added to the Runtime enum in components/buildless-serverless/api/v1alpha2/function_types.go alongside python312
• Python314 field is added to the runtime image config struct in components/buildless-serverless/internal/config/function_config.go
• The operator Helm chart and image flags include the python314 runtime image (analogous to WithImageFunctionRuntimePython312 in components/operator/internal/flags/flags.go)
• The Busola extension is updated to list python314 as a selectable runtime option in config/buildless-serverless/templates/busola-serverless-extension.yaml
• Documentation is updated: docs/user/00-20-configure-serverless.md and the runtime deprecation schedule reflect python314 availability
• FIPS validator is updated to allow python314

Testing Strategy (DoD)

• Automated unit tests covering the new runtime enum value and image resolution
• Integration test: create a python314 Function, verify it reaches Running state on k3d
• Manual smoke test on SKR (Managed Kyma Runtime)

Attachments

• Runtime implementation: components/runtimes/python314/

Related Issues

• Introduce Python Runtime 3.14 ( with Flask ) #2083 — introduced the python314 runtime code (not yet enabled)
• Rework serverless runtimes API #2292 — rework of serverless runtimes API; must be completed before this issue, as python314 should follow the new runtime API design