fix(middleware): expose app presets in public header

[GaspardKirira]

Problem

A backend project generated with:

vix new blog --template backend

uses middleware App presets in the generated MiddlewareRegistry.cpp:

app.use(vix::middleware::app::security_headers_dev(false));

This helper exists and works correctly, but it is not exposed by the public middleware include:

#include <vix/middleware.hpp>

The project only compiles when the generated file explicitly includes:

#include <vix/middleware/app/adapter.hpp>
#include <vix/middleware/app/presets.hpp>

This creates unnecessary API friction: users of the backend template should not need to know which internal app/ header contains the preset helper.

Diagnosis

The middleware behavior itself is correct.

After including vix/middleware/app/presets.hpp, the generated backend builds and runs correctly.

Verified with:

curl -i http://127.0.0.1:8080/api
curl -i http://127.0.0.1:8080/health
curl -i http://127.0.0.1:8080/api/health

The responses include the expected security headers:

X-Content-Type-Options: nosniff
X-Frame-Options: DENY
Referrer-Policy: no-referrer
Permissions-Policy: geolocation=(), microphone=(), camera=()

The /api prefix middleware also works correctly because:

X-API: true

appears on /api and /api/health, but not on /health.

So the issue is not the middleware implementation. The issue is the public include surface.

Expected behavior

This should be enough in generated backend applications:

#include <vix/middleware.hpp>

Then this should compile:

app.use(vix::middleware::app::security_headers_dev(false));

The public middleware header should expose the normal App integration helpers used by generated templates.

Fix

Expose the App integration headers through the middleware public aggregation header.

Add these includes to:

modules/middleware/include/vix/middleware/all.hpp

// app
#include <vix/middleware/app/adapter.hpp>
#include <vix/middleware/app/app_middleware.hpp>
#include <vix/middleware/app/http_cache.hpp>
#include <vix/middleware/app/presets.hpp>

Acceptance criteria

This should compile without manual edits:

vix new blog --template backend
cd blog
vix build

The generated backend should keep using:

#include <vix/middleware.hpp>

and should still compile code such as:

app.use(vix::middleware::app::security_headers_dev(false));

[GaspardKirira]

Fixed.

The issue was not the middleware behavior itself. The generated backend works correctly once the App preset header is available.

The real problem was that the public middleware include did not expose the App integration presets used by the backend template.

The public aggregation header now exposes the App integration headers, including:

#include <vix/middleware/app/adapter.hpp>
#include <vix/middleware/app/app_middleware.hpp>
#include <vix/middleware/app/http_cache.hpp>
#include <vix/middleware/app/presets.hpp>

Now generated backend projects can keep using:

#include <vix/middleware.hpp>

and compile code such as:

app.use(vix::middleware::app::security_headers_dev(false));

Verified with:

vix new blog --template backend
cd blog
vix build
vix run