fsi2 harness: RTX_FSI2O_FILLET knob (the outline's fillet radius, 5 mm = t/2 in every recorded run: a half-round tip and 5 mm root fillets vs the reference's sharp rectangle; printed in both headers) — P5-3's first problem-definition probe after the h-term was traced to the wake's strength on the background

Co-Authored-By: Claude Fable 5.1 <[email protected]>
Claude-Session: https://claude.ai/code/session_01LzcjQX7tvgn87CQCyg9Cfr

crates/specialized/rtx-fsi/tests/fsi2_harness/overset_march.rs

@@ -100,7 +100,7 @@ pub fn run_march_overset(case: BenchmarkCase, config: &OversetMarchConfig) -> Ov
     // Every setting the acceptance rule reads, printed once: P5-3 lost a
     // day to a floor of 2e-4 against the overnight marches' 1e-6.
     println!(
-        "  coupling: {} (reuse {}, ω0 {}, c1 {}), floor {:.1e}, rtol {:.1e}, stall accept {:.1e}, max subit {}, predictor {}, s = {}, patch offset {} h × {} rows, patch convection {:?}, bg convection {:?}, patch stretch {}",
+        "  coupling: {} (reuse {}, ω0 {}, c1 {}), floor {:.1e}, rtol {:.1e}, stall accept {:.1e}, max subit {}, predictor {}, s = {}, patch offset {} h × {} rows, patch convection {:?}, bg convection {:?}, patch stretch {}, fillet {} m",
         cfg.coupler,
         cfg.reuse,
         cfg.initial_relaxation,
@@ -116,6 +116,7 @@ pub fn run_march_overset(case: BenchmarkCase, config: &OversetMarchConfig) -> Ov
         super::overset::patch_convection(),
         super::overset::bg_convection(),
         super::overset::patch_stretch(),
+        super::overset::fillet(),
     );
 
     // Phase 1: rigid flag to t_release (`RTX_FSI2O_LOAD=dir` replaces the