Standardize and simplify static_assert usage

[yaakov-stein]

Some cleanup: the docs recommend static_assert() and that is what is used the most throughout the repo. Let's update the style for the few cases that don't use static_assert() currently. We'll also cleanup some static_assert's that didn't have a message and were causing warnings during the build.

Also, we use static_assert_enum_mapping where appropriate and remove instances that were unnecessary.

[github-actions]

Claude: review of facebook/bpfilter #444 (b5a70bb)

Must fix

• Commit message omits daemon component — The commit message now correctly uses lib,daemon: prefix.

Suggestions

• Commit message subcomponent helper is misleading — Fixed: subcomponent dropped from the title.
• Removing bf_static_assert from public header — src/libbpfilter/include/bpfilter/helper.h — Project is pre-v1 and the macro is a trivial wrapper; acknowledged.
• Missed static_assert without message in fixup.c — src/bpfilter/cgen/fixup.c:53 — Fixed in current revision: message string added.
• Use static_assert_enum_mapping macro — src/libbpfilter/matcher.c, src/bpfilter/cgen/fixup.c — Fixed: commit 2 adopts static_assert_enum_mapping across all applicable sites.
• static_assert_enum_mapping used for non-enum arrays — src/libbpfilter/matcher.c:1668, also lines 1710 and 1753 — _bf_ipproto_strs, _bf_icmp_type_strs, and _bf_icmpv6_type_strs are explicitly sized [UINT8_MAX + 1] arrays indexed by raw uint8_t, not enums with a _MAX sentinel. The current revision removes the assertions entirely rather than keeping them as plain static_assert(). While tautological, they document the intent and would become load-bearing if the array declaration changed. Consider restoring as plain static_assert().

Nits

• Commit body could explain motivation — The commits have no body. The style guide recommends explaining "why" in the description — a brief note about standardizing per the style guide and silencing compiler warnings would help future readers.

[qdeslandes]

Could you also fix the static_assert in matcher.c which do not have any message? It raises a warning during the build.

[qdeslandes]

LGTM, thanks!