feat(hooks): add Gemini-optimized ultrawork message with intent gate

Create dedicated Gemini ultrawork variant that enforces intent
classification as mandatory Step 0 before any action. Routes Gemini
models to the new variant via source-detector priority chain
(planner > GPT > Gemini > default). Includes anti-optimism checkpoint
and tool-call mandate sections tuned for Gemini's eager behavior.

🤖 Generated with assistance of [OhMyOpenCode](https://github.com/code-yeongyu/oh-my-opencode)

src/hooks/keyword-detector/ultrawork/source-detector.ts

@@ -4,10 +4,11 @@
  * Routing logic:
  * 1. Planner agents (prometheus, plan) → planner.ts
  * 2. GPT 5.2 models → gpt5.2.ts
- * 3. Everything else (Claude, etc.) → default.ts
+ * 3. Gemini models → gemini.ts
+ * 4. Everything else (Claude, etc.) → default.ts
  */
 
-import { isGptModel } from "../../../agents/types"
+import { isGptModel, isGeminiModel } from "../../../agents/types"
 
 /**
  * Checks if agent is a planner-type agent.
@@ -22,10 +23,10 @@ export function isPlannerAgent(agentName?: string): boolean {
   return /\bplan\b/.test(normalized)
 }
 
-export { isGptModel }
+export { isGptModel, isGeminiModel }
 
 /** Ultrawork message source type */
-export type UltraworkSource = "planner" | "gpt" | "default"
+export type UltraworkSource = "planner" | "gpt" | "gemini" | "default"
 
 /**
  * Determines which ultrawork message source to use.
@@ -44,6 +45,11 @@ export function getUltraworkSource(
     return "gpt"
   }
 
+
+  // Priority 3: Gemini models
+  if (modelID && isGeminiModel(modelID)) {
+    return "gemini"
+  }
   // Default: Claude and other models
   return "default"
 }