docs: fix the README hero snippet, resync the mirrors, and give each CLI page its own icon (#801)

* docs(readme): fix the hero snippet and resync every mirror

The hero snippet called ws.command(...), which exists in neither
language: registration is the standalone command() plus mount.register.
It is replaced with a Python example that mounts ram, redis and slack
side by side, captures python with monty, and installs a CLI, all of it
run against the published 0.0.5 packages first.

Two more corrections. The filetype sentence promised parsed PDF pages,
which the filetype removal took away, so it now says a format renders
however you register it. DeepSeek Harness joins the coding agents row.

The eleven mirrors are regenerated from the root rather than patched,
which also closes drift they had accumulated: a stale backend list, the
old CLI + daemon integrations line, a missing Grok Build entry and a
Codex link pointing at the wrong docs path.

* docs(cli): give each CLI page its own icon

Every CLI page shared icon: terminal, so the sidebar was nine identical
rows. Each now takes the icon its service already uses elsewhere in the
docs: slack, discord, github for gh, google for gws, envelope for
himalaya, book for ntn and chart-gantt for linear (matching the notion
and linear setup pages, since Font Awesome carries no brand mark for
either), and git-alt for git. gws and himalaya also get their names
spelled GWS and Himalaya; the rest stay lowercase because that is the
head word you type.

* examples(filetype): register through the public mount accessor

The example reached into ws._registry.mount_for, but ws.mount is public
and returns the same MountEntry. Output is unchanged, so the CI truth
file still matches.

examples/python/filetype/filetype.py

@@ -55,7 +55,7 @@ async def main() -> None:
     await ws.ops.write("/data/hits.tally", encode({"alpha": 3, "beta": 11}))
     await ws.ops.write("/data/notes.txt", b"plain text\n")
 
-    mount = ws._registry.mount_for("/data/")
+    mount = ws.mount("/data/")
     mount.register(
         RegisteredCommand("cat",
                           spec=SPECS["cat"],