fix: bring the docs in line with the no-admin route (release review)

Name the real trigger and CODEMAN_NO_ADMIN=0 in the READMEs and the
Installation page, add the install without git to the update tables and the
updater notes, record the installer's downloads in the supply chain section,
and say that the data directory question also removes a kept runtime.

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

docs/security-architecture.md

@@ -483,6 +483,15 @@ transient mount blip at launch poisons tmux's long‑lived cwd and crashes
   never executes. Large hand‑formatted/generated assets (`app.js`, the gesture
   bundle, vendored libs) are `.prettierignore`d for the style pass, but the NUL +
   syntax checks still cover them.
+- **Installer downloads without a package manager:** on the no-admin route
+  (`docs/wiki/Installation.md`) `install.sh` fetches and runs software no system
+  package manager vetted, each checked before it is unpacked or run. The Node.js
+  tarball is checked against the `SHASUMS256.txt` fetched from nodejs.org over the
+  same TLS connection, which proves integrity, not independent provenance: the
+  signature on that file is not checked. The tmux build is checked against a
+  SHA-256 pinned per platform in the installer. `install.sh cloudflared` takes the
+  latest cloudflared release into `~/.local/bin` unverified, as the system routes
+  take the same release, because Cloudflare publishes no checksum file.
 
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