#32310 acpmux tests: usage_stats expects the default 400K autocompact cap (base red from #31936)

Base-red-job: cmux-tui spec inventory / acpmux tests (lib, hub_integration)

fork_through::usage_stats::the_session_list_and_info_carry_what_the_chats_transcript_says fails on feat-cmux-next with left: "capped", right: "none" (usage_stats.rs:32). #31936 made acpmux start a Claude session whose Claude home sets no window with CLAUDE_CODE_AUTO_COMPACT_WINDOW=400000 (harness_limits::CLAUDE_AUTOCOMPACT_WINDOW). This test still expected the old uncapped state. It now expects capped and autocompactCap: 400000. Only the test changes.

🤖 Generated with Claude Code

Agent session: agent session

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Summary by cubic

Updates the acpmux usage_stats integration test to match the new default 400K autocompact cap introduced in #31936.

• The test previously expected autocompact to be "none" and autocompactCap to be null, which no longer holds since acpmux now starts Claude sessions with a default 400K window (CLAUDE_CODE_AUTO_COMPACT_WINDOW=400000).
• The test now asserts "capped" and autocompactCap: 400000. Only test expectations changed.