Add integration pipelines without a broker

package main

import (
    _ "embed"
    "log"
    "net/http"

    "ideaswave.com/qubit/sdk/camel"
)

//go:embed routes.xml
var routesXML []byte

func main() {
    rt, err := camel.New(routesXML, nil) // nil: no JSON-Schema validation
    if err != nil {
        log.Fatal(err)
    }
    rt.RegisterBean("loans.apply", applyHandler) // bean:loans?method=apply
    rt.RegisterBean("loans.batch", batchHandler) // bean:loans?method=batch

    mux := http.NewServeMux()
    guard := func(h http.HandlerFunc) http.HandlerFunc { return h } // your auth middleware
    if unbound := rt.Bind(mux, guard); len(unbound) > 0 {
        log.Printf("routes with no bean (they answer 501): %v", unbound)
    }
    log.Fatal(http.ListenAndServe(":8080", mux))
}

func applyHandler(w http.ResponseWriter, r *http.Request) {
    // r.Body is an application that passed the filter.
    w.WriteHeader(http.StatusAccepted)
}

func batchHandler(w http.ResponseWriter, r *http.Request) {
    // r.Body is a JSON array: every application of one portfolio.
    w.WriteHeader(http.StatusAccepted)
}

// The model the XML is parsed into: plain structs in package integration.
import "ideaswave.com/qubit/core/pkg/integration"

reg := integration.NewRegistry()
_ = reg.RegisterFilter(&integration.MessageFilter{
    ID:        "gold-only",
    Name:      "Gold tier only",
    Predicate: `tier = "gold"`, // FEEL; false means the message is dropped
    ChannelID: "svc",
})
reg.LookupFilter("gold-only").PassesVars(map[string]any{"tier": "silver"}) // false

// CorrelationContext matches a message to ONE waiting instance, once.
cc := integration.NewCorrelationContext("orderId")
cc.Register("A-17", "run_1ce49bbc5260b39423bd", "wait_payment")
cc.MatchVars(map[string]any{"orderId": "A-17"}) // the entry, now removed
cc.MatchVars(map[string]any{"orderId": "A-17"}) // nil: a second message resumes nothing