chore(version): claim free queue slot 1.59.1.0 to clear stale version-gate

Base VERSION advanced to 1.58.1.0, level with this branch, so the version
gate failed its 'VERSION must be greater than base' rule. Bump VERSION and
package.json to 1.59.1.0 — the next free slot above the queued 1.59.0.0
(#1815). The diff ^9.0.0 dependency bump is unchanged; the only consumer
(Diff.diffLines in browse) is API-compatible with jsdiff v9.

Author: genisis0x

VERSION

@@ -1 +1 @@
-1.58.5.0
+1.59.1.0

package.json

@@ -1,6 +1,6 @@
 {
   "name": "gstack",
-  "version": "1.58.5.0",
+  "version": "1.59.1.0",
   "description": "Garry's Stack — Claude Code skills + fast headless browser. One repo, one install, entire AI engineering workflow.",
   "license": "MIT",
   "type": "module",