Fix incorrect 'Linux unaffected' claim in bind-mount caveat

The previous note scoped the single-file bind-mount staleness bug to
Docker Desktop only. It actually affects ALL platforms including native
Linux: Docker bind-mounts the inode, not the path. Editors that do
atomic save (vim, nvim, VS Code, sed -i) create a new inode via
rename(), leaving the container pinned to the old unlinked one. This
is a kernel limitation (moby/moby#15793, open since 2015, unfixable).

Rewrite both the README.md caveat and the docker-compose.yml inline
note to describe the real mechanism (inode replacement), name the
affected editors, note that append-only writes are safe, and link to
the upstream issue.

docker-compose.yml

@@ -65,10 +65,12 @@ services:
       # The image ships sensible defaults (history tuning, prefix-search on
       # Up/Down arrows, fzf/zoxide integration). Uncomment to use your own:
       #
-      # NOTE: On Docker Desktop (macOS/Windows), single-file bind-mounts can
-      # silently stop propagating host edits — the file gets materialized onto
-      # the VM disk. If host changes don't appear in the container, see the
-      # "Shell defaults" section in README.md. Linux hosts are unaffected.
+      # NOTE: Single-file bind-mounts break when editors use atomic save
+      # (vim, VS Code, sed -i write a temp file then rename() over the
+      # original, creating a new inode the container never sees). This is a
+      # kernel limitation, not Docker-specific. If host edits stop appearing
+      # in the container, mount the parent directory instead — see the
+      # "Shell defaults" section in README.md.
       # - ~/.bash_aliases:/home/developer/.bash_aliases:ro
       # - ~/.inputrc:/home/developer/.inputrc:ro