fix(tmux): strict integer parsing and isActive validation in pane-state-parser

- parseInteger() now rejects malformed input like '120oops' using /^\d+$/ regex
- New parseActiveValue() validates active flag is exactly '0' or '1'
- Added regression tests for malformed integers, negative values, empty fields, non-binary active flags

src/features/tmux-subagent/pane-state-parser.test.ts

@@ -0,0 +1,72 @@
+/// <reference path="../../../bun-test.d.ts" />
+
+import { describe, expect, it } from "bun:test"
+import { parsePaneStateOutput } from "./pane-state-parser"
+
+describe("parsePaneStateOutput", () => {
+  it("rejects malformed integer fields", () => {
+    // given
+    const stdout = "%0\t120oops\t40\t0\t0\t1\t120\t40\n"
+
+    // when
+    const result = parsePaneStateOutput(stdout)
+
+    // then
+    expect(result).toBe(null)
+  })
+
+  it("rejects negative integer fields", () => {
+    // given
+    const stdout = "%0\t-1\t40\t0\t0\t1\t120\t40\n"
+
+    // when
+    const result = parsePaneStateOutput(stdout)
+
+    // then
+    expect(result).toBe(null)
+  })
+
+  it("rejects empty integer fields", () => {
+    // given
+    const stdout = "%0\t\t40\t0\t0\t1\t120\t40\n"
+
+    // when
+    const result = parsePaneStateOutput(stdout)
+
+    // then
+    expect(result).toBe(null)
+  })
+
+  it("rejects non-binary active flags", () => {
+    // given
+    const stdout = "%0\t120\t40\t0\t0\tx\t120\t40\n"
+
+    // when
+    const result = parsePaneStateOutput(stdout)
+
+    // then
+    expect(result).toBe(null)
+  })
+
+  it("rejects numeric active flags other than zero or one", () => {
+    // given
+    const stdout = "%0\t120\t40\t0\t0\t2\t120\t40\n"
+
+    // when
+    const result = parsePaneStateOutput(stdout)
+
+    // then
+    expect(result).toBe(null)
+  })
+
+  it("rejects empty active flags", () => {
+    // given
+    const stdout = "%0\t120\t40\t0\t0\t\t120\t40\n"
+
+    // when
+    const result = parsePaneStateOutput(stdout)
+
+    // then
+    expect(result).toBe(null)
+  })
+})