restructure handbook to flat-page spec

Replace the four-section dir layout with the revised flat-page spec:
- Three-page nav: Libraries, Standards, Deploy.
- libraries.md: live client-side fetch of the rethink-public org from the
  Gitea API, denylist-filtered, sorted table linking each repo, no version
  pins, graceful fallback on fetch/CORS failure.
- standards.md: house coding standards.
- deploy.md: deploy guide for rethink-net (services uid 1337, uid-agnostic
  Docker, paths/mounts, bind-mount permissions, read-only secrets).
- index.md landing card grid updated for the three sections.
- gitignore Playwright MCP artifacts.

Verified: mkdocs build --strict clean; libraries fallback renders live.
Signed-off-by: disqualifier <dev@disqualifier.me>

docs/standards.md

@@ -0,0 +1,42 @@
+# Coding Standards
+
+The house standards every Rethink Studios project follows. They keep our code
+consistent, readable, and predictable across the whole suite.
+
+## File hygiene
+
+- Files end with a **single trailing newline** (LF / Unix line endings).
+- **No trailing whitespace** on any line.
+
+## Indentation
+
+- **4 spaces** by default.
+- Respect language norms: TS/JS use **2 spaces**, Go uses **tabs**.
+- When editing an existing file, follow that file's existing indentation.
+
+## Docstrings and comments
+
+- Public functions get a **docstring**. Style: **lowercase-start, no trailing
+  period**.
+- Keep inline comments minimal — prefer docstrings. Use an inline comment only
+  where the code is genuinely complex.
+- Each module/file states its scope and purpose via a **module docstring**
+  (header string) — **not** a license or copyright header.
+
+## READMEs
+
+Every library and project has a defined **README** covering:
+
+- the install line,
+- what it does,
+- a usage example.
+
+## Linting and types
+
+- **flake8 clean**, max line length **120**.
+- **Type hints** on public functions.
+
+## Error handling
+
+- **Fail loud** — never swallow exceptions.
+- Catch the **specific** exception, and **log** it.