Adds a -l/--label CLI flag to podman kube play and wires it through
the API, bindings, and ABI so user-provided labels are applied to pods,
PVCs, and secrets created from Kubernetes YAML.
Key features:
- Labels are merged with YAML labels (CLI takes precedence)
- Validation uses Kubernetes qualified-name rules (RFC1123 subdomains)
- Value validation enforces 63-char limit and charset rules
- Separate merge and validate functions (SOLID principle)
- Uses maps.Clone for cleaner merging
Fixes:
- Removed incorrect annotations size limit from label validation
- Refactored to call annotations.IsQualifiedName for key validation
- Added proper documentation for max key length enforcement
Closes#26450
Signed-off-by: Sakthi Harish <sakthi.harish@edgeverve.com>