Add plain-language concept docs; fix docs viewer rendering; link API tokens

- New docs/concepts-{hosts,dns,access,api-tokens}.md -- plain-language
  guides aimed at less technical readers, each linking onward to the
  existing system-design-level doc for anyone who wants that detail.
  Card help links (Proxy List, Add/Edit host, DNS Provider cards,
  Users/Permissions/Groups cards) now point here instead of straight at
  Installation/Architecture.
- The "New API Token" card had no help link at all -- added, pointing to
  the new API Tokens doc.
- Fixed the in-app docs viewer rendering every docs/*.md page with a
  garbled heading + stray <hr> at the top: Jekyll front matter (meant
  only for the GitHub Pages build) was never stripped before being
  handed to the markdown renderer.
- Fixed cross-doc links never resolving in-app, since this viewer serves
  docs at /docs/<slug> with no .html suffix: rewritten to the correct
  in-app URL, first by registered slug, falling back to the doc's real
  filename (the correct, working link form on the Jekyll/GitHub Pages
  build) -- same idea as the existing image-path fix, and lets one link
  written in a doc work on both targets.

Bumps to v1.1.13.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KDEx8ghuZR61pqPXc6da9C

CHANGELOG.md

@@ -6,7 +6,15 @@ correspond to git tags (`vX.Y.Z`) and `nodejs/package.json`'s `version`.
 
 ## [Unreleased]
 
-## [1.1.12] - 2026-07-17
+## [1.1.13] - 2026-07-17
+
+### Added
+- Four new plain-language docs aimed at less technical readers, replacing the system-design-level Architecture/Installation docs as the target of most card help links: **Hosts & HTTPS**, **DNS Providers**, **Users, Groups & Permissions**, and **API Tokens**. Each links onward to the deeper technical reference for readers who want it; the technical docs link back the other way too. The personal-access-token card (previously missed entirely) now has a help link.
+
+### Fixed
+- The in-app docs viewer rendered every `docs/*.md` page with a garbled heading and a stray horizontal rule at the top — Jekyll front matter (meant only for the GitHub Pages build) was never stripped before being handed to the markdown renderer. Also fixed: cross-doc links never resolved in-app, since this viewer serves docs at `/docs/<slug>` with no `.html` suffix — they're now rewritten to the correct in-app URL (by registered slug, falling back to the doc's real filename), the same way image paths already were.
+
+Bumps to v1.1.13.
 
 ### Fixed
 - The host edit form's "Parent Wildcard" option stayed greyed out even when a valid wildcard actually existed for that host, so an already-created host could never be switched onto one from the edit modal (only brand-new hosts, via the field's `keyup` handler, ever saw it become available). The underlying `/host/lookup/:item` check also had the same self-match issue as the recently-fixed backend bug: it resolved an already-existing host to its own record instead of a sibling wildcard. Added a dedicated `/host/wildcard-parent/:item` endpoint that checks both directions, and the edit form now actually runs the check when it opens.
@@ -88,7 +96,8 @@ First tagged release. Establishes the `vX.Y.Z` tag convention that the in-app up
 - Standalone backup script (`ops/backup.sh`) for deployments not using theta-env's orchestrator — snapshots Redis and `./config`, with retention.
 - Admin-only in-app banner that checks GitHub releases every 24h and surfaces available updates.
 
-[Unreleased]: https://github.com/theta42/proxy/compare/v1.1.12...HEAD
+[Unreleased]: https://github.com/theta42/proxy/compare/v1.1.13...HEAD
+[1.1.13]: https://github.com/theta42/proxy/compare/v1.1.12...v1.1.13
 [1.1.12]: https://github.com/theta42/proxy/compare/v1.1.11...v1.1.12
 [1.1.11]: https://github.com/theta42/proxy/compare/v1.1.10...v1.1.11
 [1.1.10]: https://github.com/theta42/proxy/compare/v1.1.9...v1.1.10