This PR fixes a bug where `max u v` and `max v u` fail to match in
SymM's pattern matching. Both `processLevel` (Phase 1) and
`isLevelDefEqS` (Phase 2) treated `max` positionally, so `max u v ≠ max
v u` structurally even though they are semantically equal.
The fix has three parts:
- Eagerly normalize universe levels in patterns at creation time
(`preprocessDeclPattern`, `preprocessExprPattern`,
`mkSimprocPatternFromExpr`)
- Normalize the target level in `processLevel` before matching, using a
`where go` refactor
- Add `tryApproxMaxMax` to `processLevel` and `isLevelDefEqS`: when
positional `max/max` matching would fail, check if one argument from
each side matches structurally and match the remaining pair
Also moves `normalizeLevels` from `Grind.Util` to `Sym.Util` to avoid
code duplication, since both Sym and Grind need it.
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
