fix(xmcp): align prompt and resource loader startup behavior

[FiammaMuscari]

Summary

This PR is the follow-up requested during the review of #528.

It extends the same graceful loader startup behavior already implemented for tools to prompts and resources, while keeping the scope intentionally small and limited to the runtime and compiler pieces required for that behavior to work in the real bundled app.

What changed

• added graceful startup handling for prompt files
• added graceful startup handling for resource files
• wired prompt/resource loader reporting into server startup alongside the existing tool-loader flow
• taught the loaders to treat bundled interop modules with an empty default export as empty files, so they still follow the friendly warning path at runtime
• regenerated prompt/resource import handling when file contents change in development without rebuilding unrelated client bundles
• aligned the Next.js server lifecycle with the current loader contract used by server startup

Why

The tool-loader behavior added in #528 handled empty files and missing default exports gracefully. This follow-up applies the same behavior to prompts and resources and closes the remaining gap in the bundled HTTP example, where empty prompt/resource files can arrive at runtime as an interop-shaped module with default: {}.

Scope

This PR intentionally avoids expanding scope.

It does not add docs, tests, demo files, screenshots, or unrelated refactors. It only includes the production changes required to make prompt/resource startup behavior consistent with the existing tool-loader behavior.

Files changed

• packages/xmcp/src/compiler/index.ts
• packages/xmcp/src/runtime/adapters/nextjs/handler/server-lifecycle.ts
• packages/xmcp/src/runtime/utils/prompt-loader.ts
• packages/xmcp/src/runtime/utils/resource-loader.ts
• packages/xmcp/src/runtime/utils/server.ts
• packages/xmcp/src/runtime/utils/tool-loader.ts

Validation

Manual validation was performed with examples/template-config:

• empty prompt file -> friendly warning, startup continues
• missing default export -> friendly warning, startup continues
• syntax error -> original error still surfaces and fails loudly

Follow-up context

Requested in the review of #528:
#528

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[0xKoller]

LGTM!

Consistency with the previous PR #528, following the instructions and considerations from that review.

The only thing missing is the addition in the docs for this new behavior.

[FiammaMuscari]

Added the missing docs requested in review, consistent with #528. Pushed in 6dd88cc.

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Project	Deployment	Actions	Updated (UTC)
xmcp-website	Ready	Preview, Comment	Apr 9, 2026 2:14pm