fix(session-manager): match todo filenames exactly

Stop sibling session IDs from colliding in stable JSON storage by requiring an exact todo filename match instead of a substring filter.

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

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

src/tools/session-manager/storage.test.ts

@@ -168,6 +168,26 @@ describe("session-manager storage", () => {
     expect(todos).toEqual([])
   })
 
+  test("readSessionTodos only reads the exact session todo file", async () => {
+    // given
+    writeFileSync(
+      join(TEST_TODO_DIR, "ses_1.json"),
+      JSON.stringify([{ id: "todo_exact", content: "Exact match", status: "pending" }]),
+    )
+    writeFileSync(
+      join(TEST_TODO_DIR, "ses_10.json"),
+      JSON.stringify([{ id: "todo_collision", content: "Wrong session", status: "completed" }]),
+    )
+
+    // when
+    const todos = await readSessionTodos("ses_1")
+
+    // then
+    expect(todos).toHaveLength(1)
+    expect(todos[0].id).toBe("todo_exact")
+    expect(todos[0].content).toBe("Exact match")
+  })
+
   test("getSessionInfo returns null for non-existent session", async () => {
     // when
     const info = await getSessionInfo("ses_nonexistent")

src/tools/session-manager/storage.ts

@@ -277,7 +277,7 @@ export async function readSessionTodos(sessionID: string): Promise<TodoItem[]> {
 
   try {
     const allFiles = await readdir(TODO_DIR)
-    const todoFiles = allFiles.filter((f) => f.includes(sessionID) && f.endsWith(".json"))
+    const todoFiles = allFiles.filter((f) => f === `${sessionID}.json`)
 
     for (const file of todoFiles) {
       try {