[1.3]: three of four links fixed; the fourth is a fetch bug, not a stub

Records that loadBytes now exists on all three platforms and that
commons-io is gone, so items 1-3 of the chain are closed. The fourth —
a short download on Native — is newly visible because the first three
were cleared, and the ZipException it produces PROVES java.util.zip
works on Native. So what remains is one bug in the Native fetch rather
than another missing capability, which is a much better place to be
than where this entry started.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: reid-spencer

BACKLOG.md

@@ -357,11 +357,30 @@ each want an approved plan before implementation, per the standing rule.
   **That is Reid's call, and it is the whole of the remaining gap** — roughly 193
   of the 281 cases.
 
-  **The experiment was REVERTED, deliberately.** Steps 1 and 2 work but unlock
-  nothing while step 3 stands, and moving the files leaves two suites ABORTING on
-  Native, which is worse than not running. The knowledge is the deliverable; the
-  edit would be churn. If the decision above goes the "read a checkout" way, steps
-  1 and 2 are an hour's work and are already known to compile.
+  **UPDATED 2026-08-18: steps 1-3 are now FIXED and committed** (`e4f91525c`), on
+  Reid's steer to use sttp (already a dependency) or write the code, and with his
+  permission to extend `PlatformContext` provided all three platforms implement it.
+
+  - **`PlatformContext.loadBytes(url): Future[Array[Byte]]`** is new — the binary
+    counterpart of `load`, which returns a `String` and therefore corrupts a ZIP.
+    JVM uses `openStream`; Native uses sttp (the same stack `load` already uses
+    for text); Scala.js uses `dom.fetch` with `arrayBuffer()`.
+  - `PathUtils.copyURLToDir` no longer touches either stub.
+  - commons-io is gone from `RunCommandOnExamplesTest`.
+
+  **A FOURTH link is what remains, and it was invisible until the first three
+  were cleared**: the download arrives SHORT on Native, so unzip reports
+  `java.util.zip.ZipException: too short to be Zip`. Note what that error proves —
+  **`java.util.zip` WORKS on Native**, or it could not produce a real ZipException.
+  So this is one bug in the Native fetch, not another missing platform capability.
+  Verified with curl that the archive URL 302-redirects (0 bytes without `-L`,
+  207,955 with), and explicit redirect-following was added to the Native fetch
+  without resolving it — so the cause is elsewhere in that fetch, and that is
+  exactly where the next attempt starts.
+
+  **The three test files stay in `scalajvm`** until item 4 is fixed: moving them
+  leaves two suites ABORTING on Native, which is worse than not running them.
+  Moving them back is a one-line `git mv` each once the fetch is right.
 
   **Nearly all of the remaining gap is `commands`, and nearly all of THAT is
   `RiddlModelsRoundTripTest`'s 189 cases** — blocked on the shared-corpus