docs: drop the README limit that #274 fixed (closes #285)

The EIP-1193 error code now survives the last hop into the page, so the third standing limit in the End-to-End Tests section no longer describes the code. Verified against src/content/inpage.js (ProviderRpcError carries code and data) and tests/e2e/run.js (the page-side error is asserted, not only the wire).

README.md

@@ -185,17 +185,14 @@ to the background — with the message that would carry it required to be presen
 so that check cannot pass by observing nothing. That last one is the standing
 floor under [#157](https://git.eeqj.de/sneak/AutistMask/issues/157).
 
-Three limits of that coverage, none of them papered over. The RPC is stubbed
+Two limits of that coverage, neither of them papered over. The RPC is stubbed
 throughout, so this is **not** a real dApp against a real network with real
 funds; that remains a human pass before 1.0.0. The site-connection prompt is
 raised through `chrome.action.openPopup()`, and headless Chromium's
 browser-action popup is not a page Playwright can see or click, so that one
 prompt is driven at the URL the extension itself puts on the action — the same
 page and the same approval id, but whether a real toolbar click shows it is not
-observable here. And the EIP-1193 error code does not survive the last hop: the
-rejection that crosses the boundary carries code 4001 and is asserted to, but
-`src/content/inpage.js` rebuilds it as `new Error(message)`, so the calling page
-catches an error with no `code` property.
+observable here.
 
 Any test that drives a failure path on purpose declares the `console.error` it
 is about to provoke, via `errors.expect()`. That is not a mute: the declaration