chore: update zshy to 0.8.0 and TypeScript to 6.0.3

[yagop]

Upgrade the build toolchain to zshy 0.8.0 and TypeScript 6.0.3. TypeScript 6 rejects the deprecated baseUrl option in the examples config; remove it and make the existing path mappings relative to that config.

Keep TypeScript on 6.x because zshy uses the JavaScript compiler API and the installed TypeDoc version supports TypeScript through 6.0. Consumers can continue using TypeScript 5.

Keep the existing CJS source-map repair step: zshy 0.8.0 still emits ESM map names in CJS output (verified before running postbuild). The upstream fix in colinhacks/zshy#72 is not merged; see issue #71.

• npm run check is clean
• npm run build is clean
• Generated source files are untouched

Validation

• Frozen Bun lockfile install.
• Full repository check: 249 Bun unit tests passed.
• Node unit suite: 226 tests passed on Node 26.
• TypeDoc conversion with TypeScript 6.0.3.
• Packed ESM, CommonJS, and Bun subpath imports.
• ESM and CommonJS source-map stack traces resolve to the original TypeScript location without shipping source files.
• Separate TypeScript 5.0.4 and 5.9.3 consumers compile core/types imports in ESM and CommonJS with strict checking and skipLibCheck: false; invalid API parameters are rejected.
• Emitted JavaScript and declarations match the previous build, excluding source-map comments.

References

• zshy 0.8.0 release
• TypeScript 6.0 changes