Codecov re-check after 1255892 showed line 179 of
crates/wickra-core/src/indicators/bollinger.rs still uncovered: the
`prices.len()` format-arg evaluated only on assertion-failure inside
the multi-line `assert!(prices.len() >= period, "…got {}, period {}",
prices.len(), period)` — the cold panic path.
Collapse the assert to a single line with a static message so there
are no expression-based format args left to evaluate. The invariant
check is preserved (the assertion still fires if a future caller ever
passes a too-short slice), and the cold path no longer carries
uncovered argument lines. bollinger.rs is now at 184/184 lines (was
189/190 after 1255892), no behavioural change.