style: resolve forge lint warnings (#266) (#280)

* style: resolve forge lint warnings (#266)

* style: exclude naming lints globally instead of inline disables

Move mixed-case-function and screaming-snake-case-const into
foundry.toml exclude_lints, since the entire public API (into* casts,
u-prefixed constants) intentionally violates them. Keep the two
incorrect-shift disables in msb.t.sol: forge lint still flags
1 << msb(x), which is an intentional 2^msb computation.

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Co-authored-by: Paul Berg <prberg@proton.me>