Don't merge: Demonstrate dual package hazard

[timostamm]

This example demonstrates the dual package hazard and verifies the fix by connectrpc/connect-es#842.

For a repeatable example for the dual package hazard with various consumers see here.
For tree-shaking tests with various bundlers see here.

[timostamm]

@smaye81, can you take a look? From the code size benchmark in connect-es, tree-shaking in esbuild works, but it would be good to have confidence that that's also true for other bundlers like webpack and parcel.

[timostamm]

Thanks @smaye81 and @paul-sachs.

I've moved the tree-shaking tests out to a separate project here, and added bundlers to the dual package hazard example here.

The results with the fix from connectrpc/connect-es#842 are:

• no dual package hazard with any consumer (no FAIL with bash test.bash)
• tree shaking results are exactly the same (no diff after bash test.bash)