Replace path.join with path.resolve for absolute path handling

[BowTiedRadone]

This PR updates the codebase to use path.resolve instead of path.join for path resolution consistency. The changes include:

• Replacing join with resolve across the app.
• Ensuring all paths, such as manifest directories, deployment plans, and contract sources, are resolved to absolute paths.
• Updating related variable names and comments to reflect the new behavior.

This PR will be complete when issue #64 is fully resolved across all architectures.

[moodmosaic]

Thanks for the PR! It works as expected on Debian (as it should), but there's still an issue on Windows.

---

Works here on Debian:

• Shell: /bin/bash
• OS: Debian 12 (bookworm)
• Architecture: aarch64
• GCC: 12.2.0
• Clang: 14.0.6

---

Doesn't work here (different error than in #64):

• Shell: /bin/bash
• OS: MINGW64_NT-10.0-22631
• Architecture: x86_64
• GCC: Not installed
• Clang: Not installed

Nikos@WIN-ARM64 CLANGARM64 ~/dev/stacks/rendezvous (fix/paths-handling)
$ ./rv example/ counter test
Using manifest path: C:\Snapshot\dev\stacks\rendezvous\example\Clarinet.toml
Target contract: counter
node:internal/process/promises:389
      new UnhandledPromiseRejection(reason);
      ^

UnhandledPromiseRejection: This error originated either by throwing inside of
  an async function without a catch block, or by rejecting a promise which was
  not handled with .catch(). The promise rejected with the reason
  "unable to mutate url".
    at throwUnhandledRejectionsMode (node:internal/process/promises:389:7)
    at processPromiseRejections (node:internal/process/promises:470:17)
    at process.processTicksAndRejections (node:internal/process/task_queues:96:32) {
  code: 'ERR_UNHANDLED_REJECTION'
}

Node.js v20.18.1

[moodmosaic]

Merge after CI setup in #75 or another round of manual checks.