Simplify agent mode and re-add additional_permissions input

- Agent mode now only triggers when explicit prompt is provided
- Removed automatic triggering for workflow_dispatch/schedule without prompt
- Re-added additional_permissions input for requesting GitHub permissions
- Fixed TypeScript types for mock context helpers to properly handle partial inputs
- Updated documentation to reflect simplified mode behavior

src/modes/detector.ts

@@ -9,13 +9,7 @@ import { checkContainsTrigger } from "../github/validation/trigger";
 export type AutoDetectedMode = "tag" | "agent";
 
 export function detectMode(context: GitHubContext): AutoDetectedMode {
-  // If prompt is provided, always use agent mode
-  // Reasoning: When users provide explicit instructions via the prompt parameter,
-  // they want Claude to execute those instructions immediately without waiting for
-  // @claude mentions or other triggers. This aligns with the v1.0 philosophy where
-  // Claude Code handles everything - the GitHub Action is just a thin wrapper that
-  // passes through prompts directly to Claude Code for native handling (including
-  // slash commands). This provides the most direct and flexible interaction model.
+  // If prompt is provided, use agent mode for direct execution
   if (context.inputs?.prompt) {
     return "agent";
   }
@@ -38,7 +32,7 @@ export function detectMode(context: GitHubContext): AutoDetectedMode {
     }
   }
 
-  // Default to agent mode for everything else
+  // Default to agent mode (which won't trigger without a prompt)
   return "agent";
 }
 
@@ -47,7 +41,7 @@ export function getModeDescription(mode: AutoDetectedMode): string {
     case "tag":
       return "Interactive mode triggered by @claude mentions";
     case "agent":
-      return "General automation mode for all events";
+      return "Direct automation mode for explicit prompts";
     default:
       return "Unknown mode";
   }