merge: origin/main v1.1.0.0 into garrytan/fix-checkpoints

Main shipped browse Puppeteer parity (v1.1.0.0 — goto file://,
load-html, screenshot --selector, viewport --scale). Resolved conflicts:

- VERSION / package.json: bumped 1.0.1.0 → 1.1.1.0 (main is 1.1.0.0,
  this branch lands next).
- CHANGELOG: moved the /context-save + /context-restore entry to the
  top as v1.1.1.0, above main's v1.1.0.0.
- Migration: renamed gstack-upgrade/migrations/v1.0.1.0.sh →
  v1.1.1.0.sh (matches new version). Test path updated. Migration
  version string inside the script also updated.

No overlap between browse changes and context-save/context-restore code.
SKILL.md files regenerated via bun run gen:skill-docs --host all per
CLAUDE.md's "never resolve generated files by accepting either side"
rule. Golden fixtures (claude/codex/factory ship) regenerated.

bun test: 0 failures. Migration ownership guard: 7/7 pass (~85ms).

package.json

@@ -1,6 +1,6 @@
 {
   "name": "gstack",
-  "version": "1.0.1.0",
+  "version": "1.1.1.0",
   "description": "Garry's Stack — Claude Code skills + fast headless browser. One repo, one install, entire AI engineering workflow.",
   "license": "MIT",
   "type": "module",