Add stx-defi contract and tests to examples

[BowTiedRadone]

This PR adds the stx-defi contract to the examples, along with corresponding unit tests and newly added Rendezvous tests that can find a bug inside the contract.

Updates:

• example folder package.json, tsconfig.json, vitest.config.js turning the folder into a Clarinet project; this allows running simnet unit tests
• example folder exclusion from Rendezvous tsconfig.json
• updated the example dialers file extension to .cjs for compatibility with the current format of the example and the supported Node versions and all the references to this file

Resolves #171 as a side effect.

[BowTiedRadone]

As this PR is already fairly-sized, a follow-up PR is needed. It should contain:

• docs update to reference the new dialers file here
• docs update to use the latest version of the SIP-010 dialer here
• docs update to include stx-defi unit tests vs Rendezvous testing example + updated commands given the new format of the example directory
• a README inside the example Clarinet project (eventually pointing to docs)

[BowTiedRadone]

@moodmosaic Interesting finding implementing this PR: after the example folder became a Clarinet project (having its own package.json, tsconfig.json, etc.), the example sip010.js dialers file is no longer compatible with Rendezvous when using Node 18. For this reason, I turned it into a .cjs file so Node knows it is a CommonJS file.

This means a user working with a basic Clarinet project and using Node 18 will not be able to easily use Rendezvous along with a js dialers file in the current setup.

[moodmosaic]

The stx-defi contract addition is a solid move — it nicely surfaces how a PoX-2-style bug can be caught with rendezvous mechanics. That’s exactly the kind of thing these examples should be doing.

But: the TypeScript unit tests in example/ feel out of place. They're not in the same testing idiom we use for stx-defi (no fast-check, lots of boilerplate), and they pull in a bunch of TS scaffolding that doesn’t align with the purpose of this folder(?)

Two options:

• Drop the TS tests, and just document the behavior they demonstrate alongside the Clarity code.
• Or, move them into a dedicated folder (name of that would be?) and rewrite to match the Clarity-from-TypeScript testing pattern (leaner, property-based, more focused).

As-is, they dilute more than they add.

[moodmosaic]

It's better if we add the stx-defi.clar in the example folder in this PR and move the TS/JS part to another PR. There we can write idiomatic, example-based and/or property-based tests using fast-check.

.
|-- example
|   |-- Clarinet.toml
|   |-- contracts
|   |   |-- KEEPME
|   |   |-- cargo.clar
|   |   |-- cargo.tests.clar
|   |   |-- counter.clar
|   |   |-- counter.tests.clar
|   |   |-- stx-defi.clar
|   |   |-- stx-defi.tests.clar
|   |-- settings
|   |   `-- Devnet.toml
|   |-- sip010.js
|   |-- README.md
|   `-- ... (Clarity-focused examples and docs)
|
|-- example-ts/
|   `-- ... (Clarinet project with tests using the contracts from
|           ../example/contracts if possible.)
|
`-- ...

[BowTiedRadone]

It's better if we add the stx-defi.clar in the example folder in this PR and move the TS/JS part to another PR. There we can write idiomatic, example-based and/or property-based tests using fast-check.

.
|-- example
|   |-- Clarinet.toml
|   |-- contracts
|   |   |-- KEEPME
|   |   |-- cargo.clar
|   |   |-- cargo.tests.clar
|   |   |-- counter.clar
|   |   |-- counter.tests.clar
|   |   |-- stx-defi.clar
|   |   |-- stx-defi.tests.clar
|   |-- settings
|   |   `-- Devnet.toml
|   |-- sip010.js
|   |-- README.md
|   `-- ... (Clarity-focused examples and docs)
|
|-- example-ts/
|   `-- ... (Clarinet project with tests using the contracts from
|           ../example/contracts if possible.)
|
`-- ...

@moodmosaic This could end up hiding configuration issues. Since Rendezvous is designed to work with a Clarinet project, I can’t imagine a real use case where someone would use it outside of one. That’s what happened in #174 as well. Our example folder should match a real Clarinet project as closely as possible. Otherwise, users learning Rendezvous might get confused by an unusual folder structure.

[moodmosaic]

Yes, indeed. Perhaps all we need is a good README.md in the example directory, along with some TypeScript tests written in an idiomatic, property-based testing style.

[moodmosaic]

LGTM 💯