docs(corekit): second whole-repo pass over corekit, const and vendor (#1103)

[JarryShaw]

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Summary

#1103 second whole-repo pass, corekit slice.

• Backfill directives, template and const alike: OptionType 1.1.0 and
  AppType 1.1.1 (int, compare, hash by code; AppType's raised
  AttributeError until 1.1.1); _Field removed 1.3.0 (field.py,
  field.rst); VersionInfo str and beholder logging 1.3.0; Info
  iteration 1.3.3.
• Stale claims: PortEnumField's width check (_missing_ never raises
  in width), its isinstance sites, _validate_value's callers, the empty
  FieldMeta/VendorMeta, Vendor as a "meta class", and the IPX
  packet crawler, which does not crawl either.
• Cross-references: _missing_, ProtocolError, FieldValueError,
  struct, aenum.StrEnum, the APPTYPE page links, MH_CGAExtension
  and vendor VLAN targets, and a role split across two #: lines.
• Labels: IPv6_ExtensionHeader, HTTP_StatusCode; the vendor IPv4
  table lists TSFlag.
• Timed wording dropped from parts of the AppType template (const
  mirrored).
• Typos: a stray period in pcapkit.vendor, "enumerate registry" x5.

Template output matches both const modules. AST guard identical bar the
two templates, identical with every string blanked. tests/project,
const, vendor, corekit, dumpkit, foundation/registry and
test_docstring_contract pass.

Refs #1103

[JarryShaw]

Verdict: GOOD TO GO at a5358e12e. The first Sonnet review found four misdated backfill directives; a fix round and a Sonnet re-check, each measured over the v1.* tags, settled them:

• the value and str format change shipped in v1.0.3.post2, outside the 1.1.0–1.4.1 backfill, so it is dropped;
• OptionType's int/compare/hash moves to 1.1.0, as 1.1.0.rst credits it;
• AppType's stays at 1.1.1, because in 1.1.0's .post builds those methods read an attribute AppType never set, and they first worked in 1.1.1 (e3dd2ef11).

Each const file matches its vendor template, and the AST guard passes on all changed files. tests/project and the const, vendor and corekit tests pass.