fix: patch fallback json merge

[csatib02]

Description

Resources whose Go types use a custom MarshalJSON that hoists map entries to
top-level JSON keys — most notably opentelemetry-operator's AnyConfig fail reflective strategic-merge inside k8s-objectmatcher with:

unable to find api field in struct AnyConfig for the json field "prometheus/message_metrics_exporter"

When PatchMaker.Calculate returns an error, ReconcileResource skips the
patchResult.IsEmpty() "resource is in sync" short-circuit and issues a full
Client.Update(...) on every reconcile. The result is a generation bump on
the API server every loop, which in turn triggers the downstream operator
(opentelemetry-operator in our case) to reconcile, producing visible churn and
DEBUG log spam:

DEBUG could not match objects {"error": "Failed to generate strategic merge patch: unable to find api field in struct AnyConfig for the json field \"prometheus/message_metrics_exporter\""}

This PR introduces FallbackPatchMaker, a thin wrapper around any patch.Maker
that retries with a three-way JSON merge patch when the primary maker errors.
It is wired in as the default in NewReconcilerWith, so every consumer of
operator-tools picks it up automatically.

Behavior is unchanged for types where strategic-merge already succeeds — the
fallback path only runs on the error branch. Consumers who pass their own
WithPatchMaker(...) keep full control.

• Also bumped go version to 1.25.0 and go.mod dependencies.
• Ran go.fix.

Type of Change

• Bug Fix
• New Feature
• Breaking Change
• Refactor
• Documentation
• Other (please describe)

Checklist

• I have read the contributing guidelines
• Existing issues have been referenced (where applicable)
• I have verified this change is not present in other open pull requests
• Functionality is documented
• All code style checks pass
• New code contribution is covered by automated tests
• All new and existing tests pass