feat(event-handler): add route specific middleware registration and execution

[svozza]

Summary

This PR implements route-specific middleware functionality for the REST event handler, allowing middleware to be applied to individual routes in addition to global middleware. E.g.,

// functional
const middleware1 = async (params, options, next) => {
    console.log('middleware1-start');
    await next();
    console.log('middleware1-end');
};

app.get('/test', [middleware1], (params, {event, context, request}) => {
  return { result: 'get-decorator-middleware' };
});

// decorators
@app.get('/test', [middleware1])
public async getTest() {
    return { result: 'get-decorator-middleware' };
}

Changes

Route Class (packages/event-handler/src/rest/Route.ts)

• Added middleware property to Route class constructor with default empty array

BaseRouter (packages/event-handler/src/rest/BaseRouter.ts)

• Updated all HTTP method signatures to support optional middleware parameter: get(path, middleware?, handler)
• Added overloads for decorator syntax with middleware.
• Modified resolve() method to compose global and route-specific middleware
• Route-specific middleware executes after global middleware in execution chain

RouteHandlerRegistry (packages/event-handler/src/rest/RouteHandlerRegistry.ts)

• Updated resolve() method to include middleware in returned RouteHandlerOptions

Tests

• Created factory functions for creating middlewares to reduce code duplication
• Tests for functional middleware
• Decorator tests

Issue number: closes #4430

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[dreamorosi]

Left a few comments / questions - the implementation is quite involved but looks ok.

Fell free to request another review when ready.

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
12.5% Duplication on New Code

See analysis details on SonarQube Cloud

[dreamorosi]

I'm ok to merge this one as is, including the complexity warning from Sonar since it'll be removed once #4438 is addressed.