docs: publish docs/wiki as the user manual, with a sync workflow

30 pages covering install, concepts, the dashboard, the agent CLIs, unattended
runs, remote and Docker cases, security and the HTTP API, plus a sidebar and a
footer. The wiki repo has no CI and no review, so docs/wiki is the source of
truth and .github/workflows/wiki-sync.yml mirrors it on every push to master.

The workflow refuses to mirror when docs/wiki is missing or holds no pages,
because it deletes before it copies and would otherwise publish the deletion of
every page. The footer carries a {{VERSION}} placeholder stamped at publish
time rather than a hand-written version, which went stale on every release.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

docs/wiki/Web-Tabs.md

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+# Web Tabs
+
+Open any dashboard you run, Grafana, Uptime Kuma, Portainer, a status page on port 4000, as
+a tab beside your agent sessions. Codeman becomes one mission control instead of Codeman
+plus a pile of browser tabs.
+
+A web tab is **not a session**. There is no PTY, no tmux, and no respawn behind it, the same
+way a docker case is not a run mode.
+
+## Adding one
+
+1. Click the chevron next to **Run**.
+2. Under **Web / URL**, pick **Add URL**.
+3. Name it, paste the URL, optionally hit **Test**, and **Save**.
+
+It opens immediately and appears in the dropdown from then on. Web tabs share the tab strip
+with sessions, continue the same `Alt+1` to `Alt+9` numbering, and carry a globe icon so
+they never read as a running agent.
+
+**Closing a tab is not deleting it.** The tab's `x` closes; the `x` on its **dropdown row**
+deletes the saved dashboard. Each dropdown row also has a gear for editing the URL.
+
+Switching tabs does not reload a dashboard. Frames stay alive in the background, so one that
+took a while to authenticate is still there when you come back. Past six live frames, the
+least recently viewed is dropped to bound memory.
+
+## Why dashboards are proxied
+
+A plain cross-origin iframe fails three ways at once in the setup Codeman actually ships in:
+
+| Blocker             | What happens                                                                                  |
+| ------------------- | ----------------------------------------------------------------------------------------------- |
+| **Mixed content**   | Production is HTTPS, and browsers hard-block `http://` iframes on an HTTPS page. No override, and none at all on iOS Safari. |
+| **Framing refusal** | Grafana, Portainer, Home Assistant and many others send `X-Frame-Options: DENY`.                |
+| **Codeman's CSP**   | `default-src 'self'` blocks a cross-origin frame before it starts.                              |
+
+So by default the dashboard is served **through Codeman's own origin**: the browser loads a
+path on Codeman, and Codeman relays to the dashboard, stripping the framing refusal,
+rewriting redirects, cookies and root-absolute URLs, and relaying WebSockets so live panels
+still update.
+
+A useful side effect: the dashboard is fetched **by the Codeman server**, so a tailnet-only
+or localhost-only dashboard works from any device that can reach Codeman, including a phone
+that is not on your tailnet.
+
+There is also a `direct` mode, a plain cross-origin iframe, which is cheaper but only works
+for an HTTPS dashboard that permits framing.
+
+## The Test button, and what it does not test
+
+**Test** probes from the server and tells you which mode applies. It verifies
+**server-to-upstream reachability and nothing else**. It does not exercise the browser
+sandbox, cookies, CORS, CSP, or any reverse proxy in front of Codeman.
+
+A passing Test does not guarantee the embedded page renders.
+
+## The sandbox, and when to turn it off
+
+Because a proxied dashboard is served from Codeman's own address, the browser considers it
+same-origin with Codeman. Unchecked, its JavaScript could read the Codeman page and call the
+API that spawns agents.
+
+So the frame is sandboxed **without** same-origin access by default. The page runs in an
+opaque origin: it cannot touch Codeman, and it gets no cookies or local storage of its own.
+
+Unchecking **Open sandboxed** grants a real origin. Do that only for a dashboard you fully
+trust, and only when you need it, which in practice means one with its own login that stores
+a session in a cookie.
+
+Either way, Codeman never forwards its own credentials upstream. The `Authorization` header
+and the `codeman_session` cookie are stripped on the way out, so `CODEMAN_PASSWORD` cannot
+leak into a dashboard.
+
+## Known incompatibility: cookie-authenticated reverse proxies
+
+If Codeman itself sits behind Cloudflare Access, Authelia, oauth2-proxy, or similar, a
+**sandboxed** tab may render unstyled or broken while the Codeman page around it works fine.
+
+The reason: an opaque-origin frame's stylesheet, script, and API requests do not carry the
+proxy's authentication cookie. The proxy redirects them to the login provider, and CORS or
+CSP kills them there.
+
+Trusted mode keeps a real origin and the cookie, so it works. Test cannot catch this, because
+it checks the server's reach, not the browser's.
+
+## Security notes
+
+The proxy authenticates on an in-memory capability embedded in the path, which is why it is
+exempt from the cookie and Origin checks that every API route enforces. That exemption is
+fenced to safe methods and non-API paths, and there is a test pinning it in place.
+
+Two failure modes that only appear inside a sandboxed frame, and that curl can never
+reproduce, are handled: runtime-built root-absolute URLs escaping the injected base, and
+same-host requests being CORS-checked with a null origin. Both present as the dashboard's own
+"Failed to fetch" while the page itself renders fine.
+
+## Read next
+
+- [The Dashboard](The-Dashboard) - the tab strip these share.
+- [Security](Security) - why the sandbox default is what it is.
+- [`docs/web-tabs.md`](https://github.com/Ark0N/Codeman/blob/master/docs/web-tabs.md) - the full reference.