Fix generated Node selection and stabilize cancellation tests

[mattfaltyn]

Summary

• include JSX, MTS, CTS, and root TypeScript configuration files in newly generated Node checks
• behaviorally validate source and manifest selection for every generated stack
• prove JSX execution with a fake npm in changed-file and --all modes
• give Git cancellation integration tests the complete documented cleanup window
• prepare the source version and documentation for v2.0.4

Validation

• go test -count=100 ./internal/repo -run ^TestRootCancellation$
• go test -count=50 ./internal/app -run TestDetect|TestInitialize|TestNode
• go test -race ./...
• go vet ./...
• go build -trimpath ./cmd/intentci
• go run ./cmd/intentci --all
• go test ./... (examples/go)
• go mod tidy with no manifest diff
• workflow and configuration YAML parsing
• local darwin/arm64 archive checksum, contents, version, JSX selection, and --all smoke tests

No CLI, schema, dependency, platform, or production cancellation change.

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