feat: add kustomize unified 'patches' field support

[yxxhero]

Summary

Add support for kustomize's unified patches: field which auto-detects Strategic Merge vs JSON Patch and supports both inline content (via patch:) and external file references (via path:).

See https://github.com/kubernetes-sigs/kustomize/blob/master/examples/inlinePatch.md

Closes #94

Changes

Library API

• Add Patches []string field to ChartifyOpts and PatchOpts
• Each file may contain a single patch document, a list of patch documents, or a multi-document YAML stream
• External path: references are copied into tempDir (consistent with transformer path resolution from Usage of kustomize transformers with "path" instead of "patch" #90)
• Added jsonpatches and patch-files dirs to removedPathList for cleanup (jsonpatches was previously leaking)

CLI

• Add -patch flag (repeatable) to cmd/chartify

Usage

# inline-patch.yaml - single patch entry with inline content
patch: |-
  apiVersion: apps/v1
  kind: Deployment
  metadata:
    name: my-deploy
  spec:
    replicas: 3
target:
  kind: Deployment

# CLI
chartify -patch inline-patch.yaml -o output release chart-path

# Go library
opts := chartify.ChartifyOpts{
    Patches: []string{"inline-patch.yaml"},
}

Test plan

• Unit tests: TestParsePatchDocuments (8 cases), TestMarshalPatchEntry (2 cases), TestPatch_Patches (2 cases)
• Integration tests with snapshots: inline strategic merge, list (strategic + JSON6902), external path reference
• go fmt, go vet, go build all pass
• Existing tests unaffected (except pre-existing kube_version_and_api_versions which depends on cluster state)