[alexvalentine94]

Ruff fixes and formatting

Merge with "Create a merge commit" (not squash or rebase) so the formatting commit hash listed in .git-blame-ignore-revs stays valid.

Commits

1. ruff check --fix: 891 safe fixes across 64 files (unused imports, import sorting, modern type annotations, f-strings without placeholders, redundant pass, etc.)
   • Fixes a circular import exposed by import sorting: decomposemultiprocess now imports DecompositionSolid from decomposesolid, where it is defined, rather than from decompose
2. ruff format: 75 files reformatted, layout only. Every file parses to the same code as before.
3. .git-blame-ignore-revs: lists the format commit so git blame and GitHub's blame view skip it. Locally: git config blame.ignoreRevsFile .git-blame-ignore-revs

Results

• Ruff score: 7.83 → 9.40/10 (1,207 → 316 findings)
• Tests unchanged (352 passed, 16 skipped without OpenMC); blocking lint passes
• All 50 mcio modules import; examples and CLI run; MCNP decks from the examples are identical apart from timestamps
• Removed imports checked by hand: side-effect imports (casadi, OCP, optional openmc/cadquery) kept, and no module relied on a removed name

Remaining findings (need manual review)

316 findings that aren't auto-fixable, including mutable default arguments (B006), loop-variable closures (B023), bare/blanket except (E722, BLE001) and unused variables (F841).

Reviewing

Review commit 1 for code changes; commit 2 is formatting only (git diff -w shows nothing beyond quotes and line wrapping).