Allow multiple dependencies to be defined.

[jsuereth]

Does NOT resolve ref conflicts between dependencies or resolve version conflicts.

This sort of fixes #1358

What this does:

• Allow multiple dependencies to be defined.
• uses schema_url to figure out if something is a dependency.

What this does NOT do

• Use local repo's schema_url in any dependency resolution (i.e. we COULD have a full circle and that'd be bad).
• Attempt to resolve ref attributes or signals between dependencies with syntax - this just declares that an error and gives up.
• Allow compatible dependencies to come from multiple paths - I.e. if both B and C depend on A at different version numbers, that would still be an error for now.

This is just starting to make progress and evaluate a smaller scope. I think there may be a more significant refactoring to solve the above, so leaving this as draft while I do some more testing.

[codecov]

Codecov Report

❌ Patch coverage is 87.35632% with 11 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.8%. Comparing base (5c9baa5) to head (a991cd4).
⚠️ Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
crates/weaver_resolver/src/loader.rs	75.0%	9 Missing ⚠️
crates/weaver_resolver/src/attribute.rs	94.1%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #1368     +/-   ##
=======================================
- Coverage   81.9%   81.8%   -0.1%     
=======================================
  Files        115     115             
  Lines       9850    9892     +42     
=======================================
+ Hits        8069    8099     +30     
- Misses      1781    1793     +12     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[jsuereth]

So there are a lot of shortcuts in this PR i had to fix in #1377. Debating closing this for part 2 directly. Will check in with maintainers.

[jsuereth]

discussed with @jerbly - in the interest of smaller PRs, going to push this one for review first before the layer on top of it.