updated kf dependencies

[matix522]

Proposed Changes

• Security: Upgraded Go toolchain version to 1.26.6 across root, operator, first-party, third-party forked, sample apps, and documentation go.mod files.
• Changed: Upgraded Kubernetes (k8s.io/*) packages from v0.36.2 to v0.37.0 and updated knative.dev/pkg and knative.dev/operator (v0.50.1).
• Changed: Upgraded Go module dependencies (cloud.google.com/go/logging, github.com/docker/cli, github.com/google/go-containerregistry, golang.org/x/*, google.golang.org/api, google.golang.org/grpc, google.golang.org/protobuf) to their latest versions.
• Changed: Migrated github.com/alessio/shellescape to al.essio.dev/pkg/shellescape (v1.6.1) and github.com/imdario/mergo to dario.cat/mergo (v1.0.2), and updated pkg/sourceimage/create.go for go-gitignore API compatibility.
• Changed: Updated vendor directories and regenerated third_party/VENDOR-LICENSE.

Release Notes

* `Security`: Upgraded Go toolchain to 1.26.6 across all Kf modules and updated standard library/third-party dependencies.
* `Changed`: Upgraded Kubernetes client and API dependencies (`k8s.io/*`) to v0.37.0 and Knative Operator (`knative.dev/operator`) to v0.50.1.