Fix prototype build tooling

[mdroidian]

Summary

• resolve the shared roam-prototype CLI entry point through real filesystem paths so Windows workspace links execute correctly
• generate starters with the named runExtension utility export, avoiding a non-callable CommonJS wrapper at runtime
• prefer the pnpm cache during local integration tests while allowing missing packages to download
• strengthen regressions so a generated build must report Built dist
• add a linked-directory CLI execution test

Problems found during the stock prototype test

1. Successful no-op build: On Windows, roam-prototype build could compare its linked process.argv[1] path with the real module path, decide it was not the CLI entry point, and exit successfully without creating dist/extension.js.
2. Runtime load failure: The generated default import of roamjs-components/util/runExtension became a CommonJS module object in the ESM bundle. Roam then failed with TypeError: (0, at.default) is not a function.
3. Cold-cache test failure: The starter integration test forced --offline outside CI, so a developer without every tarball already cached failed on es-module-lexer.

The missing artifact, silent artifact skip, and interrupted dependency state observed during the test were downstream symptoms of these issues rather than separate prototype defects.

Developer impact

New prototypes now build through the normal package script on linked Windows workspaces, load the generated lifecycle wrapper correctly in Roam, and can run the integration suite with a cold or partially populated pnpm cache.

Validation

• targeted CLI and generator tests: 8 passed
• pnpm test: 29 passed
• pnpm build
• pnpm prepare:artifacts
• generated-starter integration test verifies the build reports Built dist and emits the public artifact contract

[github-actions]

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CI passed, but this branch does not contain an installable prototype yet.

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[chatgpt-codex-connector]

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[devin-ai-integration]

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