doc(ime): add the concrete fork-cleanup steps

doc/ime.md

@@ -161,6 +161,42 @@ last one.** When IME behavior is touched, run S8.
   `IME PUSH snippet/sel/commit-range` (bounded: only on change).
 - Fork-side, **temporary** (in `~/gioui`, gated by the `replace` in
   `go.mod`): `PADIME` boundary logs in `GioView.updateSelection`,
-  `GioView.restartInput`, and `window.EditorStateChanged`. Remove these,
-  drop the `replace`, `go mod tidy` — behavior is identical on stock
-  gioui. Keep until the informal on-device testing is settled.
+  `GioView.restartInput`, and `window.EditorStateChanged`.
+
+### Cleanup steps (when informal on-device testing is settled)
+
+The fork is stock v0.10.2 plus the `PADIME` lines and nothing else
+(verify first: `git -C ~/gioui diff --stat` must show only
+`app/GioView.java` and `app/os_android.go`); behavior is identical on
+stock gioui.
+
+```sh
+# 1. Restore the fork to clean v0.10.2
+git -C ~/gioui checkout -- .
+git -C ~/gioui diff --stat            # must be empty
+
+# 2. Drop the replace and re-tidy pad against stock gioui
+cd ~/pad
+go mod edit -dropreplace gioui.org
+go mod tidy
+
+# 3. Verify everything green on stock gioui
+go build ./...
+go test -race ./...
+./scripts/check.sh
+
+# 4. Rebuild both APKs and smoke-test
+./scripts/build_emu.sh                # install to emulator
+bash /tmp/s8.sh                       # full-path scenario must still PASS
+./scripts/build_phone.sh              # install to phone, type + tap once
+
+# 5. Commit and push the go.mod/go.sum change
+git add -A && git commit -m "build: drop the temporary gioui diagnostic fork" && git push origin main
+
+# 6. Remove this cleanup section (and the "temporary" fork-side bullet
+#    above) from ime.md; commit + push.
+```
+
+If step 1 shows more than the two diagnostic files, do NOT `checkout --
+.` blindly: review the diff and keep anything that is a real (non-log)
+change, porting it upstream or documenting it in this file first.