docs(#3422): the user store is one file, not two

Six places asserted the old design as fact, and none of them mention the
change by name -- the class of doc breakage that is found by asking what
a diff made untrue, not by grepping for a feature:

- swarmctl/README.md and swarm-authelia-bridge/README.md both described
  their own private canonical store. The bridge's "known limitation"
  section described the seam as unsolved; it is what this fixes, so it
  becomes what both writers must uphold instead.
- docs/swarm/{sso,ui,secrets}.md described a rendered artifact.
- The repo CLAUDE.md entry for swarmctl said the same.
- docs/tools/swarmctl-cli.md is regenerated (CI diffs it against the
  clap tree), picking up the removed --store flag.

Operator-facing where it is read: the hand-editing consequence (values
survive a rewrite, comments do not) is stated in sso.md, where an
operator is being told to edit the file, rather than only in a module doc.

docs/tools/swarmctl-cli.md

@@ -25,8 +25,9 @@ swarm-level operator CLI
 ###### **Options:**
 
 * `--authelia-bin <PATH>` — authelia binary used to hash passwords. The argon2 parameters must match the verifier's, so this has to be the *configured* package rather than whatever is on `PATH`
-* `--users-file <PATH>` — Host-side path of authelia's users database — i.e. the path inside the container, prefixed with the container's root
-* `--store <PATH>` — Canonical user store
+* `--users-file <PATH>` — Host-side path of authelia's users database — i.e. the path inside the container, prefixed with the container's root.
+
+   This is the only user store: it is read before every change and written in place, and `swarm-authelia-bridge` writes the same file.
 
 
 
@@ -40,7 +41,7 @@ Manage subjects in the swarm's SSO provider
 
 * `add` — Add a user, generating a password for them
 * `update` — Change an existing user's attributes
-* `list` — List every user in the canonical store
+* `list` — List every user in authelia's users database
 
 
 
@@ -85,9 +86,9 @@ Every flag is optional and they compose, so one call can set several things at o
 
 ## `swarmctl user list`
 
-List every user in the canonical store.
+List every user in authelia's users database.
 
-Reads `store` only — never authelia's rendered `users.yml`, which is a derived artifact this crate writes and never reads back (see the crate doc comment). One line per user: username, display name, email (if set), groups (if any).
+Read-only: it never writes the file. Shows every subject in it, including agent identities `swarm-authelia-bridge` created — one line per user: username, display name, email (if set), groups (if any).
 
 **Usage:** `swarmctl user list`