Release exp: Nix flake/NixOS module (#5431) + composer-focus shortcut (#5795). Thanks @rodboev.

#5431 (#2422): optional Nix flake + NixOS systemd module. Codex SAFE — zero non-Nix
  impact (only guarded bootstrap.py fallback touches core), secure-by-default
  (loopback, 0700/0077, non-root, EnvironmentFile secrets), 100 tests.
#5795 (#5759): Cmd/Ctrl+/ focuses composer. Codex SAFE after maintainer fix
  (matched e.key==='/' not physical Slash code so QWERTZ Ctrl+- zoom isn't stolen
  + shifted-/ works); focus-only, guarded, no conflict, 4 tests.

CHANGELOG.md

@@ -13,6 +13,10 @@
 
 - **Deep-link straight to a profile with `?profile=<name>`.** Opening the WebUI with a `?profile=NAME` query parameter now switches to that profile on boot. The name is validated against the existing profile allowlist (a nonexistent profile boots normally, path-traversal / cross-profile attempts are rejected), the switch goes through the same access-enforced `switchToProfile`, and boot fails safe on anything invalid. Thanks @rodboev. (#5730, #5682)
 
+- **Nix flake + NixOS module (optional install path).** Nix/NixOS users can now install and run the WebUI declaratively: `nix shell` for the package, or `services.hermes-webui.enable = true;` to run it as a managed systemd service. Secure by default — binds loopback-only (`127.0.0.1`), state directory is `0700`/`UMask 0077`, runs as a dedicated non-root system user, and secrets come from `environmentFiles`; network exposure requires explicitly setting both a non-loopback host and `openFirewall`. Purely additive — non-Nix installs are completely unaffected (community-supported; not covered by the project's CI). Thanks @rodboev. (#5431, #2422)
+
+- **Keyboard shortcut to focus the composer: `Cmd`/`Ctrl` + `/`.** Jump the cursor back into the message input from anywhere (sidebar, transcript, side panels) without creating a new chat. It's focus-only and a no-op while you're already typing in a field. Matches on the `/` character so it works correctly across keyboard layouts (and never intercepts browser zoom). Thanks @rodboev. (#5795, #5759)
+
 - **Send-to-first-token latency (TTFT) is now measured.** Each streamed turn records how long it took from send to the first visible token (`ttft_ms`), surfaced in metering stats and as a `_firstTokenMs` diagnostic on the message. Measurement-only — computed once on the first token with no added latency on the streaming hot path, and existing token/usage/cost metering is unchanged. Thanks @rodboev. (#6042, #6006)
 
 - **"Approve once" no longer silently sticks for the whole session.** On local (non-gateway) deployments, choosing **Approve once** on a tool approval prompt was wrongly persisting as a session-wide approval, so the next matching guarded tool call skipped its approval card. "Once" now applies to only the single call that prompted it, and the next matching call re-prompts as intended; "Approve for session" and "Always allow" are unchanged. Thanks @rudidev08. (#6035, #6017)