Sydshields/dash 1732 turn existing templates in js files

[syd-shields]

testing CI

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Note

Medium Risk
Moderate risk because it changes how filtered builds clean javascript/ output and how package.json scripts.build is rewritten, which could unintentionally delete or alter generated template artifacts.

Overview
Refactors scripts/build-javascript.mjs to parse CLI filter flags once (parseBuildOptions) and reuse the resulting options for both file filtering and output cleanup, keeping partial rebuild behavior consistent when using include/exclude template or path flags.

Updates package.json adaptation to safely drop a leading compile-only tsc from scripts.build: it now removes the script only when it’s just tsc, or preserves any chained commands after &&/||/; so downstream steps (e.g. next build) remain.

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