[Kinflou]

Stage 2 of the #219 rollout: core reads the catalog instead of keeping its own copies.

Depends on ComlineProject/specification#2 (the comline-catalog crate). It is pinned to that PR's head for now. Once that merges, I'll repin to the merge commit before merging this.

What now comes from the catalog

• Guarantee:
  • name() maps each variant to the catalog's id constant. describe() and the new description() and entry() read the catalog.
  • The enum stays hand-written. It is frozen into the IR, and each guarantee needs core's own logic for when it's given up.
  • guarantees_are_the_catalogs requires exactly the catalog's set, in its order, with each variant's frozen spelling equal to its catalog name in CamelCase. A guarantee added to the spec therefore fails core's tests until core implements it.
• Facts:
  • ProfileKind::facts() now returns the catalog's facts (an iterator of comline_catalog::Fact) instead of a hand-kept table. Nothing outside core called it.
  • Profile::parse, grammar and establishes follow. establishes reads each fact's establishes relation, and skips one core doesn't know, which fails closed.
  • The fact names in diff, compat, unverified and freezing are now the catalog's fact::* constants.
  • the_values_core_acts_on_are_the_catalogs checks that every value that logic compares with is allowed by the catalog.
  • a_profile_is_held_to_the_catalogs_facts covers parse's errors.
• Spellings: official::spellings builds each name's aliases and canonical (frozen) spelling from the catalog, replacing SPELLINGS. every_name_and_alias_resolves_as_before still passes unchanged.
• Encoding constants: FORMAT_*, FRAMING_DATAGRAM2/3, DEFAULT_HANDSHAKE, IMPLICIT_HANDSHAKE and HANDSHAKE_NONE are the catalog's constants. FRAMING_DATAGRAM and FRAMING_JSONRPC stay literal, because they're the frozen spellings; the_frozen_spellings_are_the_catalogs checks them.
• Official declarations: the_declarations_are_the_catalogs checks that the stdlib's config.idp declares exactly the catalog's encodings that have a profile, in order and with matching kinds, with has_vectors where the catalog names a feature, and that none is the one encoding not declared.

Frozen IR is unchanged: the same names and the same serde form, and the_snapshot_is_what_freezes passes.

Not in this PR: refusing unknown annotation names, settings keys and diagnostic codes (#171, #178). The catalog doesn't hold those yet.

Tested locally:

• cargo test --workspace: 633 integration and 326 lib tests pass.
• The IR-only build (--no-default-features) builds.
• No new warnings.