fix: complete the docs/→design/ and openapi→api/ rename references

The file moves (docs/ → design/, docs/api/openapi.json → api/openapi.json) landed
in d01a8fd, but the matching reference updates did not — so mgmt.rs's drift-test
`include_str!("../../../docs/api/openapi.json")` pointed at a path that no longer
exists and the host failed to build. This restores it and updates every reference:

  - mgmt.rs include_str! → ../../../api/openapi.json (fixes the build)
  - web/orval.config.ts codegen target, web/Dockerfile, .dockerignore
  - deb/rpm/Arch packaging install paths
  - CLAUDE.md, the .gitea CI workflows, code doc-comments, design-doc cross-links

docs-site route URLs (/docs/...) untouched.

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

crates/punktfunk-host/src/vdisplay/windows/pf_vdisplay.rs

@@ -6,7 +6,7 @@
 //!
 //! Control surface: a device-interface-GUID + `CreateFileW` + `DeviceIoControl` IOCTL protocol, with
 //! the wire contract OWNED by [`pf_driver_proto::control`] (versioned + `#[repr(C)] Pod` structs,
-//! NOT the SudoVDA ABI). No DLL, no named pipe. See `docs/windows-host-rewrite.md`.
+//! NOT the SudoVDA ABI). No DLL, no named pipe. See `design/windows-host-rewrite.md`.
 //!
 //! This is a faithful clone of [`super::sudovda`] (the shipping fallback) repointed at the new driver:
 //! same reference-counted/lingering monitor lifecycle, same CCD isolation + active-mode forcing — those