Document serving the docs over a LAN

Add a "Share on your LAN" blurb to both docs how-to homes
(`notes_to_self/howtodocs.md` + the dev-tips "Building these docs"
section): bind the server to all ifaces — via `sphinx-autobuild
--host 0.0.0.0` (live-reload) or `python -m http.server --bind
0.0.0.0` (static) — so a peer on your subnet can hit
`http://<lan-ip>:8000` (`hostname -I` prints the ip).

Verified a LAN-ip `curl` returns 200 + the socket binds `0.0.0.0`;
includes a trusted-LAN-only caveat since it's an unauthenticated
server on every interface.

(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code

docs/project/dev-tips.rst

@@ -156,6 +156,22 @@ every save::
         --group docs sphinx-autobuild docs docs/_build/html
     # then open http://127.0.0.1:8000
 
+**Share on your LAN**: bind the server to all interfaces
+(``--host 0.0.0.0``) instead of localhost, then hand a peer on
+your subnet ``http://<your-lan-ip>:8000``::
+
+    nix develop .#docs -c uv run --with sphinx-autobuild \
+        --group docs sphinx-autobuild docs docs/_build/html \
+        --host 0.0.0.0 --port 8000
+
+or statically serve an already-built tree (no rebuild-on-save)::
+
+    python -m http.server -d docs/_build/html --bind 0.0.0.0 8000
+
+``hostname -I`` prints the IP to share; note it's an
+unauthenticated server bound to every interface, so keep it to a
+trusted LAN.
+
 How the diagrams resolve,
 
 - ``.d2`` sources live in ``docs/diagrams/``; their rendered

notes_to_self/howtodocs.md

@@ -42,6 +42,36 @@ nix develop .#docs -c uv run --with sphinx-autobuild \
 # then open http://127.0.0.1:8000
 ```
 
+## Share it on your LAN
+
+To let someone on your subnet view the docs, bind the server to
+all interfaces (`--host 0.0.0.0`) instead of just localhost, then
+hand them `http://<your-lan-ip>:8000`.
+
+Live-reload, LAN-visible:
+
+```
+nix develop .#docs -c uv run --with sphinx-autobuild --group docs \
+    sphinx-autobuild docs docs/_build/html --host 0.0.0.0 --port 8000
+```
+
+Or just statically serve an already-built `docs/_build/html` (no
+rebuild-on-save):
+
+```
+python -m http.server -d docs/_build/html --bind 0.0.0.0 8000
+```
+
+Find the IP to give them (first one is usually your LAN iface):
+
+```
+hostname -I
+```
+
+> Heads-up: this is an unauthenticated static server bound to
+> every interface — fine on a trusted LAN, but don't leave it
+> running on an untrusted/public network.
+
 ## Diagrams (`d2`)
 
 - `.d2` sources live in `docs/diagrams/`; their rendered SVGs are