fix(catalog): add eslint catalog entry to enable upgrade prompts

ESLint was missing from the catalog, causing guide.sh to skip it during
upgrade prompts. The script only processes tools with catalog entries
(line 236: if catalog_has_tool).

Added eslint.json with:
- npm_global install method
- guide section for upgrade prompts
- order: 300 (formatters/linters group)

This fixes the issue where "make outdated" shows eslint as outdated
but "make upgrade" doesn't prompt for it.

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

Co-Authored-By: Claude <noreply@anthropic.com>

Author: CybotTM

catalog/eslint.json

@@ -0,0 +1,14 @@
+{
+  "name": "eslint",
+  "install_method": "npm_global",
+  "description": "JavaScript and TypeScript linter",
+  "homepage": "https://eslint.org",
+  "github_repo": "eslint/eslint",
+  "binary_name": "eslint",
+  "package_name": "eslint",
+  "guide": {
+    "display_name": "ESLint",
+    "install_action": "upgrade",
+    "order": 300
+  }
+}