Fix path references in dummy app after monorepo restructure

The restructure in PR #2114 moved spec/dummy/ to react_on_rails/spec/dummy/,
requiring an additional level of directory traversal to reach the monorepo root.

Changes:
- package.json: Update cd ../.. to cd ../../.. for link-source, lint, and format scripts
- Gemfile: Update Gemfile.development_dependencies path from ../../ to ../../../

Fixes CI failure: https://github.com/shakacode/react_on_rails/actions/runs/19625046694/job/56192235815

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: justin808

react_on_rails/spec/dummy/Gemfile

@@ -2,6 +2,6 @@
 
 source "https://rubygems.org"
 
-eval_gemfile File.expand_path("../../Gemfile.development_dependencies", __dir__)
+eval_gemfile File.expand_path("../../../Gemfile.development_dependencies", __dir__)
 
 gem "react_on_rails", path: "../.."

react_on_rails/spec/dummy/package.json

@@ -68,9 +68,9 @@
   },
   "scripts": {
     "preinstall": "yarn run link-source && yalc add --link react-on-rails",
-    "link-source": "cd ../.. && yarn run build && cd packages/react-on-rails && yalc publish",
-    "lint": "cd ../.. && yarn run lint",
-    "format": "cd ../.. && yarn run nps format",
+    "link-source": "cd ../../.. && yarn run build && cd packages/react-on-rails && yalc publish",
+    "lint": "cd ../../.. && yarn run lint",
+    "format": "cd ../../.. && yarn run nps format",
     "test:js": "yarn run jest ./tests",
     "test": "yarn run build:test && yarn run lint && bin/rspec",
     "test:e2e": "playwright test --config=e2e/playwright.config.js",