feat(ENG-288): Add field attributes to #[frame] for declarative constant generation

[alnoki]

Changes

1. Add comment width validation to the build injector so that
   assembly comments exceeding 75 characters fail at build time
   (cargo check / rust-analyzer), preventing overlong .equ
   comment lines in .s files
2. Extend #[frame] to accept an optional module name argument
   (#[frame("frame")]) and, when combined with #[inject] and
   #[prefix] on the struct, generate a constant group module
   directly from field-level attributes, eliminating the separate
   constant_group! block for frame-based groups
3. Support field attributes #[offset], #[unaligned_offset],
   #[pubkey_offsets], #[unaligned_pubkey_offsets],
   #[signer_seeds], #[cpi_accounts], and #[sol_instruction]
   with auto-inferred SCREAMING_SNAKE_CASE names from the field
   name, optional name overrides, and sub-field access via
   comma-separated syntax (#[unaligned_offset(NAME, sub, "doc")])
4. Support struct-level #[relative_offset(NAME, from, to, "doc")]
   for cross-field offset differences
5. Migrate RegisterMarketFrame and its constant_group! block
   to the new field-attribute syntax, making the struct the single
   source of truth for both layout and constant definitions
6. Remove _pad: u32 from CreateAccountData and rearrange the
   frame to maintain 8-byte alignment without it
7. Split macros/src/frame.rs into frame/mod.rs, frame/parse.rs,
   and frame/field_constants.rs, collapsing repeated offset match
   arms via a shared offset_kind helper
8. Update constant_group! doc comment to list all supported
   constant kinds
9. Update build-scaffolding.md docs for #[frame],
   signer_seeds!, and cpi_accounts! sections to document the
   new field-attribute workflow

[linear]

ENG-288