End-to-end publish test using examples from docs

[chlowell]

Closes #105 by adding an end-to-end test that uses publisher to publish examples from docs/server-json/examples.md to a live local registry so we can have some confidence that the examples are valid and publisher and registry work together.

sample output

Found 8 examples in "docs/server-json/examples.md"
Publishing example starting on line 6
  ✅ publisher output:
        2025/07/24 22:29:06 Using GitHub OAuth for authentication
        2025/07/24 22:29:06 {"id":"1f5ccc19-e83f-4023-b757-f3fdbcc782ab","message":"Server publication successful"}

        2025/07/24 22:29:06 Successfully published to registry!
  ✅ registry response matches example

...

published 8/8 examples
========== registry logs ==========
WARNING: "noauth" build tag has disabled authentication
2025/07/24 22:29:03 Starting MCP Registry Application v0.1.0 (commit: undefined)
2025/07/24 22:29:05 MongoDB database name: mcp-registry
2025/07/24 22:29:05 MongoDB collection name: servers_v2
2025/07/24 22:29:05 HTTP server starting on :8080

To make this possible in a local dev loop without modifying (much of) the registry's internals, I added a build tag that disables registry auth. Gating this feature behind a build tag makes it hard to enable accidentally and ensures the no-auth code doesn't exist in normal builds, and registry prints a warning when auth was disabled at build time. I also tweaked publisher to return a nonzero exit code when an operation fails.

Running the test exposed a bug fixed in this PR: a couple mongo operations used versiondetail in a key whereas the Server model uses version_detail.

I did a little reorganizing as well by moving the publish handler tests in /integrationtests, which rely on mocking internal implementations, into the existing unit test suite.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
internal/database/mongo.go	0.00%	2 Missing ⚠️

📢 Thoughts on this report? Let us know!

[chlowell]

The delta here is the tests from integrationtests/publish_integration_test.go, tweaked to use the slightly different mocks defined in this file

[tadasant]

This is awesome, thank you! Looks great.