Fix bun template install

[djeebus]

turns out bun auto reads .env.local, which we don't want

https://bun.com/docs/runtime/environment-variables

[cursor]

PR Summary

Low Risk
Low risk CI-only change, but the added rm .env.local can fail the workflow if the file doesn’t exist or the working directory changes unexpectedly.

Overview
Updates the base-template GitHub Actions workflow to explicitly remove .env.local before running bun install/build so Bun doesn’t auto-load local env vars, and tweaks the manual dispatch environment choices; consider using rm -f to avoid failing builds when .env.local is absent.

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[cursor]

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