♻️ Align primitive-union matcher names and drop stale lint disables

Rename `MatcherStrict` / `MatcherWidening` to
`PrimitiveUnionMatcherStrict` / `PrimitiveUnionMatcherWidening`, matching
the exported `getPrimitiveUnionMatcher(W)` names and the
`TaggedUnionMatcher*` pair.

Folds in the working-tree lint cleanups: drop the now-unneeded
`typescript/unified-signatures` disables and turn the tagged-union
factory interfaces into type aliases.

src/primitive-union.ts

@@ -40,11 +40,10 @@ type MustBePartial<T extends Matchable, Handled> =
 // so `Exact` restores it for the generic forms: a handler map can otherwise
 // carry keys outside `T`.
 
-// oxlint-disable typescript/unified-signatures
 // Strict returns: one common `R`. Overload order is load-bearing:
 //   #1 Handlers (first) -> the exhaustive form and the autocomplete popup
 //   #2 Fallback (last)  -> accepts a partial handler map plus a fallback
-interface MatcherStrict<T extends Matchable> {
+interface PrimitiveUnionMatcherStrict<T extends Matchable> {
     <R>(handlers: Handlers<T, R>): UnaryFn<T, R>;
     <
         R,
@@ -55,13 +54,11 @@ interface MatcherStrict<T extends Matchable> {
         fallback: Fallback<T, Handled, R>,
     ): UnaryFn<T, R>;
 }
-// oxlint-enable typescript/unified-signatures
 
 // Widened returns: the union of every handler's return type. `P` is inferred
 // from the whole handler map, whose closed constraint supplies the
 // contextual/autocomplete type.
-// oxlint-disable typescript/unified-signatures
-interface MatcherWidening<T extends Matchable> {
+interface PrimitiveUnionMatcherWidening<T extends Matchable> {
     <P extends Exact<Handlers<T, unknown>, P>>(
         handlers: P,
     ): UnaryFn<T, PatternReturns<P>>;
@@ -74,7 +71,6 @@ interface MatcherWidening<T extends Matchable> {
         fallback: Fallback<T, Handled, R>,
     ): UnaryFn<T, PatternReturns<Handled> | R>;
 }
-// oxlint-enable typescript/unified-signatures
 
 const dispatch =
     (handlers: HandlerMap, fallback?: UnaryFn<never, unknown>) =>
@@ -101,7 +97,7 @@ const dispatch =
 
 export const getPrimitiveUnionMatcher = <
     T extends Matchable,
->(): MatcherStrict<T> => dispatch;
+>(): PrimitiveUnionMatcherStrict<T> => dispatch;
 export const getPrimitiveUnionMatcherW = <
     T extends Matchable,
->(): MatcherWidening<T> => dispatch;
+>(): PrimitiveUnionMatcherWidening<T> => dispatch;