refactor(model-fallback): fully encapsulate session state in factory closure

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/plugin/hooks/create-core-hooks.ts

@@ -1,4 +1,5 @@
 import type { HookName, OhMyOpenCodeConfig } from "../../config"
+import type { ModelFallbackControllerAccessor } from "../../hooks/model-fallback"
 import type { PluginContext } from "../types"
 import type { ModelCacheState } from "../../plugin-state"
 
@@ -10,15 +11,17 @@ export function createCoreHooks(args: {
   ctx: PluginContext
   pluginConfig: OhMyOpenCodeConfig
   modelCacheState: ModelCacheState
+  modelFallbackControllerAccessor?: ModelFallbackControllerAccessor
   isHookEnabled: (hookName: HookName) => boolean
   safeHookEnabled: boolean
 }) {
-  const { ctx, pluginConfig, modelCacheState, isHookEnabled, safeHookEnabled } = args
+  const { ctx, pluginConfig, modelCacheState, modelFallbackControllerAccessor, isHookEnabled, safeHookEnabled } = args
 
   const session = createSessionHooks({
     ctx,
     pluginConfig,
     modelCacheState,
+    modelFallbackControllerAccessor,
     isHookEnabled,
     safeHookEnabled,
   })

src/plugin/hooks/create-session-hooks.ts

@@ -1,4 +1,5 @@
 import type { OhMyOpenCodeConfig, HookName } from "../../config"
+import type { ModelFallbackControllerAccessor } from "../../hooks/model-fallback"
 import type { ModelCacheState } from "../../plugin-state"
 import type { PluginContext } from "../types"
 
@@ -69,10 +70,11 @@ export function createSessionHooks(args: {
   ctx: PluginContext
   pluginConfig: OhMyOpenCodeConfig
   modelCacheState: ModelCacheState
+  modelFallbackControllerAccessor?: ModelFallbackControllerAccessor
   isHookEnabled: (hookName: HookName) => boolean
   safeHookEnabled: boolean
 }): SessionHooks {
-  const { ctx, pluginConfig, modelCacheState, isHookEnabled, safeHookEnabled } = args
+  const { ctx, pluginConfig, modelCacheState, modelFallbackControllerAccessor, isHookEnabled, safeHookEnabled } = args
   const safeHook = <T>(hookName: HookName, factory: () => T): T | null =>
     safeCreateHook(hookName, factory, { enabled: safeHookEnabled })
 
@@ -171,6 +173,7 @@ export function createSessionHooks(args: {
             .catch(() => {})
         },
         onApplied: enableFallbackTitle ? updateFallbackTitle : undefined,
+        controllerAccessor: modelFallbackControllerAccessor,
       }))
     : null