feat: add open-rpc linter to ci

[shanejonas]

Adds initial passing linting for the openrpc document.

For now just checks if info.title exists as well as method.summary, we can expand support as we go.

I tried to add a lint rule for examples but simulate currently doesn't have any examples so I left it out for now.

[MysticRyuujin]

1. Merge conflict

The PR targets an older version of .github/workflows/test.yaml. The workflow has since been restructured (Go bumped to ^1.26, jobs split, Install speccheck removed as a standalone step). This currently
shows as dirty/unmergeable and will need a rebase.

2. Misleading rule name

In openrpc-lint.yml, the rule is named info-title but checks for the description field:

  info-title:               # <-- says "title"
    ...
    then:
      field: "description"  # <-- checks "description"

Should either be renamed to info-description, or the field changed to title.

3. Unpinned @latest dependency in CI

run: go install github.com/shanejonas/openrpc-linter@latest

Using @latest means a future release of openrpc-linter could silently break CI. Should be pinned to a specific version, e.g. @v0.0.1.

4. openrpc-linter is the author's own tool

Worth flagging that this adds a CI dependency on a personal repo with a single release (v0.0.1, July 2025). Not disqualifying, but the project should be comfortable taking on that dependency before merging.