- Change N=1->2 split policy from down to right to establish 2 full-height columns
- Share single decision table across GUI and headless modes
- Add _full_height_pane guard to prevent half-height column splits
- Quadruple-wire default max_columns=2 and max_rows=2 across layout.py, lib.sh, and .mam.env.example
- Update unit and integration tests to enforce deterministic 2x2 grid trajectory
- I-2: add 5.0s upper-bound execution time assertion in test_bug4_headless_unobservable_fast_path to contractually guard SKS_EMPTY_GIVEUP early-exit latency
- I-3: clean up PaneInfo.focused, wire MAM_MAX_PANE_COLS/MAM_MAX_COLS environment variables and CLI --max-cols flag
- C-1: apply max_columns growth guard to headless 0x0 layouts, mirroring GUI behavior
- Promoted Planner consensus plan Rev.2 (plan-fea5f1b2.md) and unanimous PASS reports from Reviewers Claude (report-55d1a1d9.md) and Cline (report-6f18ba0f.md)
- Verified all 333 test cases pass with exit code 0
Godopu