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>

packaging/windows/drivers/pf-vdisplay/Cargo.toml

@@ -1,6 +1,6 @@
 # pf-vdisplay — the all-Rust UMDF IddCx virtual-display driver (M1 step-2 rewrite onto wdk-sys + the
 # owned pf-driver-proto ABI). Replaces the vendored-binding oracle at packaging/windows/vdisplay-driver/
-# (deleted once on-glass parity is reached, per docs/windows-host-rewrite.md §14 STEP 8).
+# (deleted once on-glass parity is reached, per design/windows-host-rewrite.md §14 STEP 8).
 [package]
 name = "pf-vdisplay"
 edition.workspace = true