fix: close the review findings on the issue wave

Two reviewers over the #1345/#1348/#1349 wave; no blockers, two
majors, several minors — all fixed.

- La16 was still billed at 4 B/px: the no-conversion special case
  keyed on native_bpp == 4, which La16 also is — but only Rgba8 is a
  real move in into_rgba8, so La16's decode peak is 8. The case now
  keys on the color type, and a table test pins every layout's peak
  (plus GIF's screen+frame 8) so the accounting can't silently drift.
- A control-routed open of a damaged-but-recoverable drawing parked
  the operation behind the RecoveryPrompt modal (hang until the JS
  timeout, silent drop if another op arrived, or false success when a
  human declined). The open op now settles as failed with
  recovery_required and the parse error; the prompt stays for humans,
  automation can retry through the recovery flow.
- json_values_match: integers beyond f64 precision compared by value
  (a u64 could round-trip-match a float); integral pairs now compare
  exactly and mixed integer/float matches only when the float is whole
  and equals the integer.
- A queued web open settles with the explicit queued marker whenever
  the open slot was busy (the old name check made same-named in-flight
  opens look completed with an empty result).
- ocs-control.js resolves  with the API object reference, not
  window.ocsControl (undefined if the bridge already existed when the
  script ran); DATALINK on web says the typed path is superseded by
  the picker instead of silently discarding it; the wipeout depth test
  probes past the page background's rectangle; and the plot-path doc
  comment names the function it actually mirrors.

web/ocs-control.js

@@ -21,7 +21,10 @@
   let readyResolve;
   const ready = new Promise(resolve => { readyResolve = resolve; });
   const settle = () => {
-    readyResolve(window.ocsControl);
+    // apiObject is assigned to window.ocsControl at the END of this IIFE;
+    // resolve with the local reference so a synchronous bridge (script
+    // injected late) cannot settle `ready` with undefined.
+    readyResolve(apiObject);
     window.dispatchEvent(new Event("ocs-ready"));
   };
   const poll = setInterval(() => {
@@ -68,5 +71,7 @@
     return reply;
   }
 
-  window.ocsControl = {ready, request};
+  const apiObject = {ready, request};
+
+  window.ocsControl = apiObject;
 })();