Handle _.context syntax/import failures without crashing startup

[Copilot]

Summary

A broken _.context.ts (syntax/import error) previously bubbled into startup failure paths. This change makes context-module load failures non-fatal: Counterfact now warns and skips that context module, while continuing to load routes.

• Context load error handling
  • In ModuleLoader.loadEndpoint, context files (_.context.*) now take a dedicated error path on import failure.
  • Instead of registering route-style 500 handlers or throwing, loader writes a warning and returns.
• Route error behavior unchanged
  • Non-context route modules still keep existing behavior (500 responder registration for import/syntax failures).
• Docs update
  • Added explicit note in state docs that invalid _.context.ts is skipped with a warning.
• Release metadata
  • Added a patch changeset describing the behavior change.

if (this.isContextFile(pathName)) {
  const warning = isSyntaxError
    ? `Warning: There is a syntax error in the context file: ${displayPath}`
    : `Warning: There was an error loading the context file: ${displayPath}`;

  process.stdout.write(`\n${warning}\n`);
  return;
}

Original Prompt

Issue title: App should not crash due to syntax error in _.context.ts

Issue description: A syntax error in _.context.ts should not cause the app to crash. Instead it should print a warning and not load the context module.

Manual acceptance tests

• Start Counterfact with a project whose routes/_.context.ts contains invalid syntax; verify startup continues and a warning is printed mentioning the context file.
• With the same invalid _.context.ts, call a normal route module in that tree and verify it still responds (app remains operational).
• Confirm the broken context is not applied (state/methods from that context are unavailable) until the file is fixed.
• Introduce a syntax error in a route file (not _.context.ts) and verify existing route-error behavior is unchanged (generated 500 response path still applies).

Tasks

• Added context-specific import-error handling in src/server/module-loader.ts to warn + skip for _.context.*.
• Added focused regression test in test/server/module-loader.test.ts for invalid _.context.js behavior (warning emitted, route still loaded, context not registered).
• Updated docs in docs/features/state.md to document warning-and-skip behavior for invalid context files.
• Added patch changeset in .changeset/free-numbers-relate.md.