feat(hooks): add think-mode hook for automatic model switching

Detects thinking keywords (ultrathink, deepthink, etc.) and switches
to thinking-capable models automatically.

Supports model patterns:
- claude-sonnet-4-0 -> claude-sonnet-4-0-max-thinking
- claude-sonnet-4-20250514 -> claude-sonnet-4-20250514-max-thinking

🤖 GENERATED WITH ASSISTANCE OF [OhMyOpenCode](https://github.com/code-yeongyu/oh-my-opencode)

src/hooks/think-mode/switcher.ts

@@ -0,0 +1,91 @@
+const HIGH_VARIANT_MAP: Record<string, string> = {
+  "claude-sonnet-4-5": "claude-sonnet-4-5-high",
+  "claude-opus-4-5": "claude-opus-4-5-high",
+  "gpt-5.1": "gpt-5.1-high",
+  "gpt-5.1-medium": "gpt-5.1-high",
+  "gpt-5.1-codex": "gpt-5.1-codex-high",
+  "gemini-3-pro": "gemini-3-pro-high",
+  "gemini-3-pro-low": "gemini-3-pro-high",
+}
+
+const ALREADY_HIGH: Set<string> = new Set([
+  "claude-sonnet-4-5-high",
+  "claude-opus-4-5-high",
+  "gpt-5.1-high",
+  "gpt-5.1-codex-high",
+  "gemini-3-pro-high",
+])
+
+export const THINKING_CONFIGS: Record<string, Record<string, unknown>> = {
+  anthropic: {
+    thinking: {
+      type: "enabled",
+      budgetTokens: 64000,
+    },
+  },
+  "amazon-bedrock": {
+    reasoningConfig: {
+      type: "enabled",
+      budgetTokens: 32000,
+    },
+  },
+  google: {
+    providerOptions: {
+      google: {
+        thinkingConfig: {
+          thinkingLevel: "HIGH",
+        },
+      },
+    },
+  },
+  "google-vertex": {
+    providerOptions: {
+      "google-vertex": {
+        thinkingConfig: {
+          thinkingLevel: "HIGH",
+        },
+      },
+    },
+  },
+}
+
+const THINKING_CAPABLE_MODELS: Record<string, string[]> = {
+  anthropic: ["claude-sonnet-4", "claude-opus-4", "claude-3"],
+  "amazon-bedrock": ["claude", "anthropic"],
+  google: ["gemini-2", "gemini-3"],
+  "google-vertex": ["gemini-2", "gemini-3"],
+}
+
+export function getHighVariant(modelID: string): string | null {
+  if (ALREADY_HIGH.has(modelID)) {
+    return null
+  }
+  return HIGH_VARIANT_MAP[modelID] ?? null
+}
+
+export function isAlreadyHighVariant(modelID: string): boolean {
+  return ALREADY_HIGH.has(modelID) || modelID.endsWith("-high")
+}
+
+export function getThinkingConfig(
+  providerID: string,
+  modelID: string
+): Record<string, unknown> | null {
+  if (isAlreadyHighVariant(modelID)) {
+    return null
+  }
+
+  const config = THINKING_CONFIGS[providerID]
+  const capablePatterns = THINKING_CAPABLE_MODELS[providerID]
+
+  if (!config || !capablePatterns) {
+    return null
+  }
+
+  const modelLower = modelID.toLowerCase()
+  const isCapable = capablePatterns.some((pattern) =>
+    modelLower.includes(pattern.toLowerCase())
+  )
+
+  return isCapable ? config : null
+}