refactor(claw): the forge kind is the integration's — config.rs carries no forge code

The last forge content in config.rs was vocabulary, not data:
`ForgeKind` (name/parse/token_env/default_base) and the pure
`resolve_token` helper. By the same rule that moved `Watch` to the
watch table and left `CalendarWatch` in the calendar integration,
the kind belongs to the crate that speaks the forges.

- `rhema-forge-integration` gains `kind::ForgeKind` and
  `resolve_token`, with the parse and token-fallback tests moved
  alongside — the claw's config tests were testing the integration's
  type through a re-export.
- The claw's surfaces import the type from the integration directly;
  the crate root re-exports it, so `rhema_claw::ForgeKind` keeps
  resolving for everything downstream.

config.rs is now config: credentials, the surface, paths, cadence,
and nothing that knows what a forge or a calendar is.

integrations/rhema-forge-integration/src/lib.rs

@@ -52,6 +52,8 @@ pub mod error;
 pub mod event;
 pub mod forge;
 pub mod gitea;
+pub mod kind;
+pub use kind::{ForgeKind, resolve_token};
 pub mod github;
 pub mod gitlab;
 pub mod triage;