Make websafe bundle avoid core dependency

[seveibar]

Motivation

• The browser/websafe build was pulling in a heavy runtime path (via @tscircuit/core → graphics-debug / pretty) that injects a TTY shim into the generated dist/browser bundle, breaking the intent of the websafe entrypoint.

Description

• Added a local normalizePinLabels implementation at lib/utils/normalize-pin-labels.ts and replaced the websafe import to use it instead of @tscircuit/core.
• Updated lib/convert-easyeda-json-to-tscircuit-soup-json.ts to import the local helper and re-exported it from the package entry (lib/index.ts).
• Added a regression test tests/websafe/browser-bundle-websafe.test.ts that runs the browser build and asserts the bundle does not contain known non-websafe artifacts (TTY shim, pretty, graphics-debug).

Testing

• Ran bun test tests/normalize-pin-labels.test.ts and all tests passed.
• Ran bun test tests/websafe/browser-bundle-websafe.test.ts which builds the browser bundle and the guard passed (no TTY/pretty/graphics-debug patterns found).
• Ran bun test tests/fetch-tests/c2040.test.ts which passed.
• Ran typecheck with bunx tsc --noEmit, bun run build, and bun run format, all of which completed successfully.

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Codex Task