style: apply ruff auto-fixes across codebase

- Fix import sorting (isort) across all engine modules
- Fix SIM105 try-except-pass patterns (contextlib.suppress)
- Fix nested with statements in tests
- Fix unused loop variables

Run 'uv run pytest' to verify tests still pass.

engine/effects.py

@@ -7,8 +7,8 @@ import random
 from datetime import datetime
 
 from engine import config
-from engine.terminal import RST, DIM, G_LO, G_DIM, W_GHOST, C_DIM
 from engine.sources import FEEDS, POETRY_SOURCES
+from engine.terminal import C_DIM, DIM, G_DIM, G_LO, RST, W_GHOST
 
 
 def noise(w):