chore(release): v1.9.19 — UI a11y labels for NVDA / Narrator (#1015)

Bumps Cargo.toml v1.9.18 → v1.9.19 and ships the changelog. User-visible
binary changes since v1.9.18:

- UI a11y: widgets now associate with visible labels via
  `.labelled_by(label_id)`, so NVDA / Narrator read the field name
  instead of just the control type. Fixes #916. Verified by
  @brightening-eyes (the blind user who reported the issue).

Also rolling up the exit_node Content-Encoding fix (c437598 / #964) in
the changelog — that's an asset-only commit (exit_node.ts), no Rust
binary change for it, but worth flagging in the release notes so
existing exit-node users know to redeploy their .ts script.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Cargo.lock

@@ -2624,7 +2624,7 @@ dependencies = [
 
 [[package]]
 name = "mhrv-rs"
-version = "1.9.18"
+version = "1.9.19"
 dependencies = [
  "base64 0.22.1",
  "bytes",