♻️ Move type-aware config to .oxlintrc.json; use source-level disable directives

Cleaner separation of concerns:
- options.typeAware: true in .oxlintrc.json activates type-aware
  rules declaratively (equivalent to --type-aware CLI flag, but
  the script command stays clean: just 'oxlint ...')
- Remove the 3 type-aware rule disables from .oxlintrc.json
- Add source-level oxlint-disable directives instead:
  - 4x typescript/no-unsafe-type-assertion (pattern.ts: keysMatch
    Object.keys() cast, candidate[] cast; structuralMatcher value
    as S cast; match.ts: handler as ... cast in nextCases)
  - 1x typescript/no-unnecessary-type-parameters (pattern.ts:
    keysMatch <S extends object>)
  - 1x file-level typescript/no-floating-promises in index.test.ts
    (expectTypeOf() is a sync type-assertion library that the
    type-aware linter misidentifies)

Disabling rules at the source (next to the line that needs the
exemption) documents intent more clearly than a global config
override, and makes the trade-off visible to anyone reading the
code. Re-enabling a rule in the future only requires removing the
inline comment, not editing a central config.

src/index.test.ts

@@ -1,3 +1,4 @@
+/* oxlint-disable typescript/no-floating-promises -- expectTypeOf() is a sync type-assertion library that the type-aware linter misidentifies as a promise */
 import { strict as assert } from "node:assert";
 import { test } from "node:test";