Rename internal/proxy to internal/servewaf (closes #173)

The package passes nothing on since the one-process mode went: it answers rproxy's questions, takes its reports and answers servewaf's own endpoints. It is now named after the command it serves, with `git mv`, and its constructor is `servewaf.New`. `SPEC.md` and the other documents follow. No change of behaviour.

Model: opus-5-5

internal/rproxy/request.go

@@ -16,9 +16,9 @@ import (
 	"sync/atomic"
 	"time"
 
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
 	"sneak.berlin/go/smallwebwaf/internal/rules"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 )
 
 // flushAfterEachWrite has ReverseProxy pass on each part of the app's answer as
@@ -129,7 +129,7 @@ func (rq *request) readFirstPartOfBody() bool {
 	}
 
 	_ = rq.rc.SetReadDeadline(rq.requestDeadline())
-	held, err := io.ReadAll(io.LimitReader(rq.body, proxy.QuestionBodyMaxBytes))
+	held, err := io.ReadAll(io.LimitReader(rq.body, servewaf.QuestionBodyMaxBytes))
 	// From here on, the request timer ends a read of the rest of the body, so that
 	// the answer can name the side rproxy was waiting on.
 	_ = rq.rc.SetReadDeadline(time.Time{})
@@ -384,7 +384,7 @@ func (rq *request) finish(ctx context.Context) {
 		return
 	}
 
-	report := &proxy.Report{
+	report := &servewaf.Report{
 		RequestID:     rq.id,
 		Status:        min(rq.out.status, reportStatusMax),
 		RequestBytes:  requestBytes,