fix(protocols): data and schema packages omit names their submodules export #1807

Describe the bug
Several protocol packages do not re-export classes that their submodules list in __all__, the same gap #1797 fixes for L2TP:

• pcapkit.protocols.data.internet from mh: the *Message classes and the option, suboption and attribute classes; the schema package has the same gap.
• pcapkit.protocols.data.misc from pcapng: PacketBlock, PACK_FlagsOption and PACK_HashOption; same on the schema side.
• pcapkit.protocols.data.application from httpv2: Settings.
• The hopopt and ipv6_opts data and schema modules: SMFDPDOption and QuickStartOption.
• Schema only: ipv4.Option, ipv6_route.RoutingType, and the helper functions in ipv6_option.

So from pcapkit.protocols.data import * (or schema) lacks names that the modules export.

Expected behavior
Each package re-exports what its submodules export, under the <protocol>_<name> alias the siblings use where names would clash. Names that are deliberately module-only (helpers, for example) are recorded as such where the public-API sweep (tests/project/test_public_api.py) checks them. A test pins the rule for every protocol package, so the next module cannot reopen the gap.

Additional context
Found while fixing #1797 (PR #1806) and re-derived by its Sonnet review. Part of the #1103 sweep's follow-ups.