chore(migration): switch org to wickra-lib and maintainer email to wickra.lib@gmail.com (#59)

Introduce repo-metadata.toml as single source of truth for repo identity
(org slug, maintainer email, canonical URLs) and add sync-metadata.yml
workflow with a Python audit script that fails CI if any tracked file
drifts back to pre-migration values.

Bulk-replace across 24 tracked files:
- kingchenc/wickra -> wickra-lib/wickra (URL segment)
- kingchencp@gmail.com -> wickra.lib@gmail.com (maintainer email)
- @kingchenc -> @wickra-lib (CODEOWNERS mention only)

Person-name credits are preserved: LICENSE copyright holder, Cargo.toml
authors handle, and CHANGELOG historical @kingchenc reference all remain
unchanged. Crate / PyPI / npm package names also untouched.

Merge this PR only after the kingchenc/wickra -> wickra-lib/wickra org
transfer has happened on the GitHub side, otherwise all badges and
repository links 404 until the transfer is performed.

CONTRIBUTING.md

@@ -76,9 +76,9 @@ wasm-pack test --node bindings/wasm
 - **Bindings.** A change to a public indicator API must be mirrored across the
   Python, Node, and WASM bindings, including their type stubs / `.d.ts`.
 - **Docs.** Update the relevant page on the
-  [project Wiki](https://github.com/kingchenc/wickra/wiki) and the
+  [project Wiki](https://github.com/wickra-lib/wickra/wiki) and the
   `README.md` when behaviour or the public API changes. The Wiki lives in
-  a separate git repository: `https://github.com/kingchenc/wickra.wiki.git`.
+  a separate git repository: `https://github.com/wickra-lib/wickra.wiki.git`.
 - **Changelog.** Add an entry under `## [Unreleased]` in `CHANGELOG.md`.
 
 ## Commit and pull-request workflow