fix(web): reject a reshaped replay param, and forward a declared JSON body

Copilot's sixth pass generated no new inline comments; both suppressed ones
were right.

- `arguments` surviving the key check is not the same as being sent as
  written. `replayProtocolRequest` applies `arguments ?? {}`, so a `null` shown
  in the editor reaches the wire as `{}`; an array or scalar is not nullish and
  rides the cast into a call whose type says it is a named-argument record.
  `reshapedReplayParam` rejects both before Send. `name` and `uri` are
  deliberately not checked there — the dispatch already refuses those with a
  reason the caller shows as a toast, so they fail visibly rather than
  silently.

- `NetworkEntry` never forwarded the body's content type, so the Network tab
  could not reach the declared-JSON branch at all and a malformed
  `application/json` response read as plain text with no sign it was meant to
  be JSON. Forwarded — but only when the declared type *is* JSON: passing it
  wholesale would also route an HTML body into the sandboxed frame and a CSV
  one into a table, which is a change to what the Network tab is and not one
  this makes.

The `NetworkEntry > Auth Success` play function moved off `textContent` for
body assertions. Ace repaints its rows on an animation frame and virtualizes
them, so reading the DOM straight after Reveal returned the previous rows
under load — it passed in isolation and failed in the full run. It now reads
the editors' documents alongside the DOM text, and waits.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UL9retfvAXRgvi6EWk4SY4
Signed-off-by: cliffhall <cliff@futurescale.com>

clients/web/src/components/groups/EditReplayModal/EditReplayModal.tsx

@@ -2,7 +2,10 @@ import { useState } from "react";
 import { Alert, Button, Group, Modal, Stack, Text } from "@mantine/core";
 import { JsonEditor } from "../../elements/JsonEditor/JsonEditor";
 import { isJsonObject } from "../../../utils/jsonObjectDraft";
-import { replayableParams } from "../../../lib/protocolReplay";
+import {
+  replayableParams,
+  reshapedReplayParam,
+} from "../../../lib/protocolReplay";
 import { isSerializableJson } from "@inspector/core/json/jsonUtils.js";
 
 export interface EditReplayModalProps {
@@ -106,6 +109,12 @@ function parseParamsDraft(
       } so this matches what is sent`,
     };
   }
+  // Surviving the key check is not the same as being sent as written: see
+  // `reshapedReplayParam` for the two ways `arguments` does not.
+  const reshaped = reshapedReplayParam(method, parsed);
+  if (reshaped !== null) {
+    return { ok: false, error: reshaped };
+  }
   return { ok: true, value: parsed };
 }