docs(P6.4): repoint all doc links from the GitHub wiki to docs.wickra.org (#86)

The documentation now lives in the wickra-lib/wickra-docs VitePress repo and
will deploy to docs.wickra.org. Rewrite every tracked, user-facing wiki link
in the main repo to the new canonical site:

- docs/README.md, CONTRIBUTING.md, PULL_REQUEST_TEMPLATE.md
- bindings/{node,python,wasm}/README.md, examples/wasm/README.md
- repo-metadata.toml: wiki_url/wiki_git -> docs_url/docs_git

Page paths map 1:1 to VitePress clean URLs (e.g. /wiki/Quickstart-Rust.md ->
docs.wickra.org/Quickstart-Rust). The sync-about.yml wiki-sync step is left
untouched on purpose: it stays until the docs site is live (tracked as P8.3).
The GitHub wiki itself is not deleted yet for the same reason.

bindings/python/README.md

@@ -48,10 +48,10 @@ identical values — the equivalence is enforced by the test suite.
 ## Documentation
 
 The full indicator catalogue, guides, quickstarts, and API reference live in
-the main repository and wiki:
+the main repository and documentation site:
 
 - **Repository & full indicator list:** <https://github.com/wickra-lib/wickra>
-- **Wiki** (quickstarts, cookbook, TA-Lib migration): <https://github.com/wickra-lib/wickra/wiki>
+- **Docs** (quickstarts, cookbook, TA-Lib migration): <https://docs.wickra.org>
 - **Runnable examples:** [`examples/python/`](https://github.com/wickra-lib/wickra/tree/main/examples/python)
 
 Wickra ships four bindings — Python, Node.js, WebAssembly, and Rust — that all