Bring the documentation up to the published site and fill its gapsdocs/current-state

The documents still described a site in maintenance with two languages and
a forum page with a language menu. They now describe what is published, and
three documents are new.

New, under Documents/:
- README.md: index of the documentation.
- ARCHITECTURE.md: the frontend, the backend and the forum page, what each
  serves, what the site deliberately does not contain, and how search
  engines and crawlers are treated.
- LOCALIZATION.md: the four languages, how a page picks one, what counts as
  a visitor's choice, how Hebrew text is laid out, where the text lives and
  how to add a language.
- DEVELOPMENT.md: requirements, the commands of each part, the dependency
  locks and checksums, the tests and what CI enforces.

Updated:
- README.md: the site is public; four languages and the browser-language
  default; a documentation section; the Dokka gate.
- CONTENT.md: the forum notice without a language menu; translation rules
  for four languages, including preferring the term a reader would use over
  a literal one; the crawler rules as an owner decision.
- OPERATIONS.md: the live route table; the release steps for the directory
  layout on the server, with the SELinux labelling order that caused an
  outage once; cache keys for the forum files and CDN caching; maintenance
  mode as a fallback instead of the current state; rollback by directory;
  checksum regeneration with --refresh-dependencies; the post-release check
  for four languages and right-to-left text.

No source file changes.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 102 insertions, 0 deletions

diff --git a/Documents/ARCHITECTURE.md b/Documents/ARCHITECTURE.md
new file mode 100644
index 0000000..c11cfea
--- /dev/null
+++ b/Documents/ARCHITECTURE.md
@@ -0,0 +1,102 @@
+<!-- SPDX-FileCopyrightText: 2026 Progmasoft <support@progmasoft.com> -->
+<!-- SPDX-License-Identifier: AGPL-3.0-or-later WITH AdditionRef-Progmasoft-Patent-Grant-1.1 -->
+
+# Architecture
+
+The repository has three independent parts. Each is built and deployed as its own artifact, and none of them stores
+anything about a visitor on a server.
+
+| Part | Technology | Artifact | Serves |
+| --- | --- | --- | --- |
+| `frontend/` | Vue 3, Vite, TypeScript | static files in `frontend/dist/` | `xsharp-lang.xyz` |
+| `backend/` | Kotlin on JVM 25, Spring Boot | one executable jar | `xsharp-lang.xyz/api/v1/site` |
+| `forum/` | one HTML page with plain CSS and JavaScript | the five files as they are | `forum.xsharp-lang.xyz` |
+
+```text
+browser
+   |  HTTPS
+   v
+Nginx
+   |-- xsharp-lang.xyz           static files of the Vue build; unknown paths fall back to index.html
+   |-- xsharp-lang.xyz/api/v1/site   ->  http://127.0.0.1:5086  (Spring)
+   |-- forum.xsharp-lang.xyz     five named static files; every other path is 404
+   `-- www, docs, spec, viget    permanent redirects
+```
+
+## Frontend
+
+A single-page application with three routes, defined in `frontend/src/main.ts`:
+
+| Route | Page | Source |
+| --- | --- | --- |
+| `/` | why the language exists, and its current state | `pages/HomePage.vue` |
+| `/docs/overview` | the design direction and the compiler stages | `pages/OverviewPage.vue` |
+| `/docs/getting-started` | building the compiler from its repository | `pages/GettingStartedPage.vue` |
+
+Any other path redirects to `/`. The router uses history URLs, so the server must answer unknown paths with
+`index.html`.
+
+The rest of the frontend is small:
+
+- `App.vue` is the shell: header, navigation, language menu, theme button and footer.
+- `locales.ts` holds the list of languages and the pure rules for choosing one. It touches neither the page nor
+  storage, which is why the tests can import it directly.
+- `preferences.ts` holds the current language and theme as reactive values, applies them to the page, and stores a
+  choice in the browser.
+- `seo.ts` sets the title, description, social metadata and canonical URL of each route in each language.
+- `styles/site.css` is the only stylesheet. Fira Sans is served from the site itself; there is no request to a
+  third-party font service.
+
+Each page keeps its text next to its template, one object per language. See [Localization](LOCALIZATION.md).
+
+## Backend
+
+The backend is deliberately tiny. It has two endpoints:
+
+| Endpoint | Returns |
+| --- | --- |
+| `GET /api/v1/site` | the name, the development phase, the fallback locale, the published locales and whether the forum is open |
+| `GET /health` | an empty 200 for the local service manager; not proxied to the public |
+
+It binds to loopback only. It has no database, no account, no package and no registry endpoint, and its tests assert
+that those routes are absent. The frontend renders without it; nothing on the three pages depends on the endpoint
+today.
+
+Nginx proxies exactly `/api/v1/site`. Every other `/api/` path is answered with 404 by Nginx, so adding an endpoint
+to the backend does not publish it.
+
+## Forum page
+
+`forum.xsharp-lang.xyz` is a notice that the forum is not open yet. It is not a forum: there are no accounts, no
+posts and no service behind it. The page shows its one notice in the language of the browser and offers a theme
+button; it has no language menu and stores no language. It is marked `noindex` in the page and in the response
+header.
+
+The page is independent of the Vue application. It shares no code with it, and its strict content security policy
+allows only its own script, stylesheet and two images.
+
+## What the site does not contain
+
+- **Accounts and packages.** Progmasoft accounts and the ViGet package registry belong to the Progmaweb repository
+  and live on `progmasoft.com` hosts. This site links to neither a sign-in nor a registry.
+- **A legacy redirect only.** `viget.xsharp-lang.xyz` redirects permanently to `viget.progmasoft.com`, keeping path
+  and query. That redirect is routing compatibility, not a feature of this site.
+- **Visitor data.** The language and theme a visitor chose are kept in the browser's local storage. The site sets no
+  cookie and sends nothing about the visitor to the backend.
+
+## Search engines and crawlers
+
+- `sitemap.xml` lists exactly the three routes above.
+- Every route has its own title, description and canonical URL. A language is a preference, not a second URL, so
+  there are no `hreflang` alternatives.
+- `robots.txt` names the crawlers the site has a rule for. Search and answer-retrieval crawlers are allowed. Among
+  the crawlers that collect training data, Google-Extended and ClaudeBot are allowed and GPTBot is disallowed; the
+  file is the authority for the full list.
+- The initial HTML carries the English metadata of the homepage. The metadata of the other routes and languages is
+  set by JavaScript after the page loads.
+
+## Security headers
+
+Nginx sends a content security policy that allows only same-origin resources, plus HSTS, `X-Content-Type-Options`,
+`X-Frame-Options: DENY` and a referrer policy. The policy has no exception for third-party scripts; a script injected
+by an intermediary, such as an analytics beacon added by a CDN, is blocked by the browser.