Fix most clang-tidy issues

[schwehr]

Some of these should be ignored, but there are likely lots of important things to fix.

e.g.

cd src/libais/
cp ais.h ais.hxx
/usr/bin/clang-tidy-19 -checks='*' ais.hxx -- -std=c++20 | grep warning | grep ']' | cut -d\[ -f2- | cut -d\] -f1 | sort -u

gives:

• cert-int09-c,readability-enum-initial-value
• cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays
• cppcoreguidelines-avoid-magic-numbers,readability-magic-numbers
• cppcoreguidelines-avoid-non-const-global-variables
• cppcoreguidelines-explicit-virtual-functions,hicpp-use-override,modernize-use-override
• cppcoreguidelines-macro-usage
• cppcoreguidelines-non-private-member-variables-in-classes,misc-non-private-member-variables-in-classes
• cppcoreguidelines-pro-type-member-init,hicpp-member-init
• cppcoreguidelines-special-member-functions,hicpp-special-member-functions
• fuchsia-overloaded-operator
• google-global-names-in-headers
• hicpp-use-equals-default,modernize-use-equals-default
• llvm-header-guard
• llvmlibc-implementation-in-namespace
• llvmlibc-inline-function-decl
• llvmlibc-restrict-system-libc-headers
• misc-non-private-member-variables-in-classes
• modernize-use-trailing-return-type
• performance-enum-size
• readability-avoid-const-params-in-decls
• readability-identifier-length
• readability-redundant-member-init