Wire Kustomize activation through scan and CLI

[whitemerch]

Tip

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Summary

• wire Kustomize detection and resolver activation through scanner walk and scan setup paths
• add finding dedupe for shared-base overlay outputs and adjust scan plumbing accordingly
• refactor scan/analyzer/provider paths to satisfy lint checks while keeping behavior stable

Full design context and architecture details: #113

Test plan

• go test ./pkg/scan/... ./pkg/analyzer/... ./pkg/engine/provider/... -count=1
• $(go env GOPATH)/bin/golangci-lint run ./pkg/scan/... ./pkg/analyzer/... ./pkg/engine/provider/... ./cmd/scanner/...

Notes

• stacked on top of PR Add Kustomize detector line mapping #116
• fixtures and end-to-end scenario verification are in the next PR

[datadog-datadog-prod-us1]

🎯 Code Coverage (details)
• Patch Coverage: 61.45%
• Overall Coverage: 47.30% (+0.21%)

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