feat: Index behaviors by return typing strategy

* Adds the concept of, and options for, the return typing strategy
  * adds the strategy at the beginning of every behavior index
  * adds the strategy as an additional argument to resolve
  * No actual use of return type strategy so far
  * Sets up eslint
  * Fixes eslint errors

package.json5

@@ -4,6 +4,7 @@
   description: 'Sequel to mathjs as prototype for mathjs overhaul',
   scripts: {
     test: 'mocha ./**/*.spec.js',
+    lint: 'eslint -c etc/eslint.config.mjs',
   },
   keywords: [
     'math',
@@ -16,6 +17,9 @@
     url: 'https://code.studioinfinity.org/glen/nanomath.git',
   },
   devDependencies: {
+    '@eslint/js': '^9.25.1',
+    eslint: '^9.25.1',
+    globals: '^16.0.0',
     mocha: '^11.1.0',
   },
   dependencies: {