Say the query logger drops bound values (closes #535)

The comment on MaxAccessLogLineBytes said the GORM adapter logs each
statement with the client's parameter written into it. Its
ParamsFilter drops every bound value, so the statement is logged with
its placeholders. The comment now says so and keeps the parts that
still hold: the widest line spends two budgets and the adapter's test
checks it against this constant.

The assertBounded doc no longer claims each line was cut, and the
postReceiver doc no longer explains itself by a log size test that is
gone.

Model: opus-5-5

internal/gormlog/gormlog_test.go

@@ -146,7 +146,7 @@ func openDB(
 }
 
 // assertBounded holds every line the adapter wrote to the stated
-// ceiling and proves each was cut rather than merely short.
+// ceiling and proves no line carried a whole client value.
 func assertBounded(t *testing.T, out string) {
 	t.Helper()
 

internal/handlers/logbound_test.go

@@ -191,13 +191,12 @@ func receiverRouter(h *handlers.Handlers) *chi.Mux {
 	return router
 }
 
-// postReceiver sends one POST at /h/<segment>.
+// postReceiver sends one POST with an empty body at /h/<segment>
+// through router and returns the response status.
 //
 // RawPath is cleared after parsing so chi routes on the decoded path
 // and the handler sees the raw bytes rather than their percent-escaped
-// spelling. That is the harder case for the budget: the escaped
-// spelling is plain ASCII, which costs one byte per byte, while the
-// decoded bytes are what the log handler has to escape.
+// spelling.
 func postReceiver(
 	t *testing.T, router *chi.Mux, segment string,
 ) int {

internal/middleware/middleware.go

@@ -115,16 +115,15 @@ const (
 	// a caller on a parameterised route would supply, which is the
 	// only way those caps can be pinned at all.
 	//
-	// One writer in that set is not a handler's own slog call. The
-	// GORM adapter in internal/gormlog logs the statement with the
-	// client-chosen parameter already interpolated into it, which on
-	// the receiver and login lookups is exactly the value the budgets
-	// above exist for. Its widest line spends two logfield.MaxBytes
-	// budgets — the statement and the driver error — against a fixed
-	// portion smaller than this one's, and
-	// internal/gormlog/gormlog_test.go asserts every line it emits
-	// against this constant directly rather than leaving it as
-	// arithmetic.
+	// The GORM adapter in internal/gormlog writes through slog as well.
+	// It logs each statement with its placeholders rather than the
+	// values bound to them (see its ParamsFilter), so the key a client
+	// sends to the receiver or login lookup does not reach its lines.
+	// Its widest line spends two logfield.MaxBytes budgets — the
+	// statement and the driver error — against a fixed portion smaller
+	// than this one's, and internal/gormlog/gormlog_test.go asserts
+	// every line it emits against this constant directly rather than
+	// leaving it as arithmetic.
 	//
 	// What it does NOT cover, so that the figure above is not read as
 	// more than it is: