refactor(hooks): split preemptive-compaction.ts to comply with 200 LOC module rule

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

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

src/hooks/preemptive-compaction-types.ts

@@ -0,0 +1,41 @@
+export interface TokenInfo {
+  input: number
+  output: number
+  reasoning: number
+  cache: { read: number; write: number }
+}
+
+export interface CachedCompactionState {
+  providerID: string
+  modelID: string
+  tokens: TokenInfo
+}
+
+export interface PreemptiveCompactionClient {
+  session: {
+    messages: (input: {
+      path: { id: string }
+      query?: { directory: string }
+    }) => Promise<unknown>
+    summarize: (input: {
+      path: { id: string }
+      body: { providerID: string; modelID: string; auto?: boolean }
+      query: { directory: string }
+    }) => Promise<unknown>
+  }
+  tui: {
+    showToast: (input: {
+      body: {
+        title: string
+        message: string
+        variant: "warning"
+        duration: number
+      }
+    }) => Promise<unknown>
+  }
+}
+
+export interface PreemptiveCompactionContext {
+  client: PreemptiveCompactionClient
+  directory: string
+}