[BUG] clang-tidy warnings and errors

[dmah42]

Describe the bug
ran clang-tidy across the codebase and collated the issues

let's work through them (i wanted to keep them somewhere handy)

clang-tidy-issues.txt

[dmah42]

updated: clang-tidy-issues.txt

[devtejasx]

maybe we should start by running clang-tidy on CI (or even on pre-commit) before we add more fixes

It already runs on CI — .github/workflows/clang-tidy-lint.yml, on every push and pull request, run-clang-tidy over the whole compile database. What it cannot do is fail: WarningsAsErrors in .clang-tidy is empty, so clang-tidy exits 0 and the findings scroll past a green check mark.

Here is what the last green run on main (30818016611) actually reported — 1256 findings, top ten checks:

check	count
misc-include-cleaner	316
cppcoreguidelines-avoid-magic-numbers / readability-magic-numbers	289
cppcoreguidelines-pro-bounds-array-to-pointer-decay	132
misc-const-correctness	129
cppcoreguidelines-avoid-c-arrays	59
cppcoreguidelines-pro-bounds-pointer-arithmetic	42
misc-non-private-member-variables-in-classes	38
cppcoreguidelines-pro-type-vararg	35
cppcoreguidelines-avoid-non-const-global-variables	31
readability-function-cognitive-complexity	12

The long tail is small: below those, every remaining check is in single digits, and 13 of them fire fewer than three times.

That suggests a way to make the job mean something without a 1256-finding cleanup first: enforce per check. Put a check in WarningsAsErrors once its findings are at zero, and it can never come back; the rest keep being reported as they are now. The cheap ones to start with are at the bottom of the list rather than the top.

I've put up a PR doing that for the two checks that are cheapest of all — misc-use-anonymous-namespace and readability-static-definition-in-anonymous-namespace, 13 findings between them, all mechanical — as a concrete example of the shape. Happy to drop the .clang-tidy hunk from it if you'd rather settle the policy separately.