feat(spec): add options/options_from for dynamic config values

Add options field for static value lists and options_from for dynamic file-based options. options_from uses JSONPath to extract values from local JSON files (e.g., account names from config). Update schema with validation rules. Add --manifest flag as preferred discovery method (offline, version-matched). Reorder discovery priority: installed tool → well-known URL → HTML link → direct URL → local file. Update examples and documentation

examples/ironlicensing.json

@@ -30,7 +30,11 @@
       "type": "string",
       "required": false,
       "arg": "--profile",
-      "prompt": "Account profile (leave empty for default)"
+      "prompt": "Account profile (leave empty for default)",
+      "options_from": {
+        "file": "~/.ironlicensing/config.json",
+        "path": "$.accounts[*].name"
+      }
     },
     {
       "key": "api-key",