test(rtx-fsi): coupling rescue rung A' — increment trigger (CRESCUE_INC=<K>), default off

Trigger (c) of omni-cortex docs/coupling_rescue_campaign.md §11: a
predictor increment above K x its trailing-2000 median (non-rescued
steps; median refreshed every 10 steps) opens a coarse episode (rung C)
BEFORE the step's first pass — no pass is spent on a step the episode
replaces. Calibrated on the INCTRACE dumps: the anchor u=1.00 r=1 stays
under 1.72x for its whole march (K = 2..8 never fire); the (1.27, 2.0)
death crosses 3x at 145 steps before its panic and never during
resonant growth (the tip-jump trigger fires at 54). Registered K = 3,
fallback 4. Needs CRESCUE=1 and CRESCUE_COARSE=<M>.

Verified: FSI2 committed default digit-identical knob-off vs the
same-day baseline; fmt + clippy clean on the touched files.

Co-Authored-By: Claude Fable 5.1 <[email protected]>
Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2

crates/specialized/rtx-fsi/tests/turek_hron_fsi2.rs

@@ -164,6 +164,7 @@ fn fsi2_flapping_flag() {
             coupling_rescue: false,
             coarse_episode: 0,
             inc_trace: None,
+            increment_factor: 0.0,
             c1_interface: false,
             predictor: "structure".into(),
             quiescent_release: false,