## What this PR does
Fixes field selector filtering for registry resources (Applications,
TenantModules, TenantSecrets) when using kubectl with field selectors
like `--field-selector=metadata.namespace=tenant-kvaps` or
`metadata.name=test`.
Controller-runtime cache doesn't support field selectors natively, which
caused incorrect filtering behavior. This PR implements manual filtering
for `metadata.name` and `metadata.namespace` field selectors in List()
and Watch() methods.
Changes:
- Created `pkg/registry/fields` package with `ParseFieldSelector`
utility for common field selector parsing
- Refactored field selector logic in application, tenantmodule, and
tenantsecret registries to use the common implementation
- Implemented manual post-processing filtering after label-based queries
- Removed `Raw` field usage and field selectors from
`client.ListOptions`
### Release note
```release-note
[registry] Fix field selector filtering for kubectl queries with metadata.name and metadata.namespace selectors
```
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