feat(ms-ai-architect): vendor playground-design-system v0.1 [skip-docs]

Initial sync of shared/playground-design-system/ into
plugins/ms-ai-architect/playground/vendor/playground-design-system/
via scripts/sync-design-system.mjs.

Source commit: f1fecf39b8fc20e86f6ec3c737f0dfda8403712e
Files: 25 (7 CSS + 11 fonts/licenses + 3 schemas + README + MANIFEST)

Vendored copy keeps the plugin standalone — playground will load CSS
from ./vendor/ regardless of where the plugin is installed.

Also adds .gitleaks.toml at repo root with a path allowlist for
vendored MANIFEST.json files (SHA-256 file hashes are not secrets).

Docs updated together with the playground HTML refactor that actually
consumes the vendored CSS (next commit). This commit is internal-only.

playground/vendor/playground-design-system/fonts/LICENSES.md

@@ -0,0 +1,42 @@
+# Font Licenses
+
+All three font families bundled with Playground Design System are licensed
+under the SIL Open Font License, Version 1.1 (OFL-1.1). They are free to
+use, modify, embed, and redistribute under the terms of OFL-1.1.
+
+Full license text per family:
+
+- **Inter** (Regular, Medium, SemiBold, Bold) — `LICENSE-Inter.txt`
+  Copyright (c) 2016 The Inter Project Authors
+  Source: https://github.com/rsms/inter
+  Version bundled: 4.0
+
+- **JetBrains Mono** (Regular, Medium, SemiBold) — `LICENSE-JetBrainsMono.txt`
+  Copyright 2020 The JetBrains Mono Project Authors
+  Source: https://github.com/JetBrains/JetBrainsMono
+  Version bundled: 2.304
+
+- **Source Serif 4** (Regular, Semibold) — `LICENSE-SourceSerif4.md`
+  Copyright 2014–2023 Adobe (Reserved Font Name "Source")
+  Source: https://github.com/adobe-fonts/source-serif
+  Version bundled: 4.005
+
+## Provenance
+
+Files in this directory were obtained from the upstream release artifacts
+linked above on 2026-05-03. Source Serif 4 woff2 files were generated locally
+from the desktop OTF release using `fonttools ttLib.woff2 compress`; all
+others are unmodified from upstream webfont releases.
+
+## Why bundled
+
+These fonts ship with the design system to eliminate runtime requests to
+external CDNs (e.g., fonts.googleapis.com). This guarantees:
+
+- No data leakage about end-user IPs / User-Agents to third parties.
+- GDPR compliance for Norwegian public-sector deployments.
+- Functioning Playgrounds in offline / air-gapped environments.
+
+Each Playground HTML loads `../shared/playground-design-system/fonts.css`,
+which declares all `@font-face` rules pointing at the .woff2 files in this
+directory.