Fix workspace linking and update scenario paths

[rjcorwin]

Summary

• ensure the CLI rewrites .mew/package.json to use file: links for the local workspace, registers stored tokens for HTTP participants, and resolves the bridge binary from the unified package
• update the bridge launcher to detect the built bridge implementation and refresh scenario scripts to point at the new packages/mew template and bridge locations
• refresh documentation references so release and bug guides describe the new package layout under packages/mew

Testing

• npm run build
• npm test

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https://chatgpt.com/codex/tasks/task_e_68da8deb346c83258ba0c74f017b927f