refactor(lsposed): mStackedLinks rewrite only on actual changes

The else-branch in sanitizeLinkProperties' stacked-links loop set
`modified = true` whenever `stackedCopy !== value`, i.e. after any
successful clone. Cloning is the common case (the catch fallback is
just a defensive shim for a missing copy ctor), so the flag was
effectively always-true: every non-empty stacked map triggered the
trailing `stacked.clear() + putAll(filtered)`, even when no VPN data
was present and no modification happened.

Drop the `stackedCopy !== value` disjunct. `modified` now reflects
only real sanitization changes — the rewrite is skipped when there's
nothing to write back, and the clones in `filtered` are discarded
along with the never-mutated original entries staying in place. No
behavioural change for VPN-stripping callers; just less wasted work
on the non-VPN-bearing path.

lsposed/app/src/main/kotlin/dev/okhsunrog/vpnhide/HookEntry.kt

@@ -125,7 +125,13 @@ class HookEntry : IXposedHookLoadPackage {
                             filtered[key] = stackedCopy
                         }
                     } else {
-                        if (stackedModified || stackedCopy !== value) modified = true
+                        // Only mark `modified` if sanitization actually
+                        // changed something. The previous condition also
+                        // tripped on `stackedCopy !== value`, which is
+                        // true after every successful clone — so any
+                        // non-empty stacked map forced a clear+putAll
+                        // even when no VPN data was present.
+                        if (stackedModified) modified = true
                         filtered[key] = stackedCopy
                     }
                 }