Store and show an event's query string, and pass it on to an HTTP target when set (closes #312)

The receiver keeps the query string of the request it received on the event, in a new `raw_query` column of the per-webhook `events` table; a resubmitted copy carries its original's. The event log and the event's page show it with the request, the event log leaving out one over 32 KiB as it does request headers. The archive and log targets carry it. An HTTP target gets a `forwardQuery` setting, off by default, on both target forms and in the target list: on, each delivery, replays and resubmits included, appends the query string to the target URL, joined with `&` to one it already has.

Model: opus-5-5

internal/delivery/target_http.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"net/url"
 	"sort"
 	"sync"
 	"time"
@@ -32,6 +33,11 @@ type HTTPTargetConfig struct {
 	URL     string            `json:"url"`
 	Headers map[string]string `json:"headers,omitempty"`
 	Timeout int               `json:"timeout,omitempty"`
+
+	// ForwardQuery passes each event's query string on to the target,
+	// appended to URL. Off, the target URL is sent exactly as
+	// configured.
+	ForwardQuery bool `json:"forwardQuery,omitempty"`
 }
 
 // httpCore holds the retry, backoff, and circuit-breaker
@@ -444,6 +450,10 @@ func (t *httpTarget) doHTTPRequest(
 		)
 	}
 
+	if cfg.ForwardQuery {
+		appendQuery(req.URL, event.RawQuery)
+	}
+
 	originScoped := applyRequestHeaders(
 		req, event, cfg, t.eng.userAgent(),
 	)
@@ -474,6 +484,19 @@ func (t *httpTarget) doHTTPRequest(
 	return resp.StatusCode, string(body), dur, nil
 }
 
+// appendQuery adds an event's query string to a delivery's URL, joined
+// with "&" to any query string the target URL already has.
+func appendQuery(u *url.URL, rawQuery string) {
+	switch {
+	case rawQuery == "":
+		return
+	case u.RawQuery == "":
+		u.RawQuery = rawQuery
+	default:
+		u.RawQuery += "&" + rawQuery
+	}
+}
+
 // clientForRequest returns the client for one delivery attempt.
 // originScoped is the header set applyRequestHeaders built for that
 // attempt; a request with neither a per-target timeout nor an