clean-codelisted

# Clean Code Judgment cues for code inside any layer. These record where this codebase's owner differs from common defaults. Apply them over generic best practice. - **Optimize total reading cost, never function length.** Length is a weak signal. The real signals are deep nesting and long boolean chains. Extract a helper only when its name lets the caller be read without opening the body. A linear forty-line function often beats eight scattered helpers. Shattering one coherent operation across a file is the same complexity in a different outfit. - **Keep related code close.** A helper used once, meaningful only beside its caller, belongs next to its caller. Every extraction adds a reader jump. Extract for clarity, never to relocate complexity somewhere less visible. - **Temper DRY.** Unify duplication only when two sites express one rule that must stay in sync. A wrong abstraction costs more than a little repetition. Flags and branches accumulating in a shared function prove the abstraction was wrong. Prefer the duplication. - **Name intent at call sites.** Raw literals and bare booleans hide meaning exactly where calls are read. Use named constants, enums, or named arguments whenever meaning is not obvious in place. The constant explains meaning, never restates the value: `MAX_RETRIES`, never `THREE`. - **Guard early.** Handle edge cases and errors at the top and return. The happy path stays at the lowest indentation level. - **Errors carry