docs: update README + docs site for public readiness

Refresh the README and documentation for public visitors:

- README: public-facing rewrite with accurate status for all four native
  clients (macOS, Linux, Windows, Android) and the Windows host.
- docs site: fix stale client status (Android is a full client, not a
  scaffold; Windows client is stage-1 complete + signed MSIX), add the
  missing Android client section, correct "which client" guidance.
- Windows host: corrected from "deferred/scoped" to implemented & shipping
  (NVIDIA-only, x64-only) across windows-host, roadmap, status,
  requirements, running-as-a-service, and the README.
- Remove internal infrastructure from public docs (box names, private IPs,
  SSH/token commands, deploy topology); rewrite status.md as a public
  project-status page; sanitize ci.md and implementation-plan.md.
- Update clients/android and clients/apple READMEs to current state.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docs-site/content/docs/host-cli.md

@@ -17,7 +17,7 @@ punktfunk-host serve --native
 
 | Flag | Meaning |
 |---|---|
-| `--native` | Also run the native `punktfunk/1` server (recommended; enables the Apple app and discovery). |
+| `--native` | Also run the native `punktfunk/1` server (recommended; enables the native clients and discovery). |
 | `--native-port <PORT>` | Native QUIC port (default `9777`). |
 | `--open` | Don't require pairing — serve any device on the network. Off by default; only for trusted single-user setups. |
 | `--mgmt-bind <IP:PORT>` | Management API address (default loopback `127.0.0.1:47990`). |