chore(release): v3.19.0 — TUI large-prompt reliability (#130) + proxy-purity context (#4) (#134)

Release prep only: bump package.json 3.18.0 → 3.19.0, CHANGELOG entry, README TUI
"what changes / what doesn't" note that the host CLAUDE.md/auto-memory is never injected.

Bundles two already-merged, independently-reviewed TUI fixes:
- #130 (PR #131): reliable large multi-line paste + version-robust turn detection.
- #4   (PR #132): never inject host CLAUDE.md / auto-memory into proxied turns.

Both verified live on PI231 + Oracle; adversarial multi-host battery passed
(0 hangs / 0 crashes / 0 injection / 0 leaks). Follow-up: #133.

No server.mjs change in this PR (package.json + CHANGELOG + README only) → cli.js
citation N/A. release_kit (Iron Rule 5.5): version_source=package.json, changelog,
README docs all updated; no new env var / endpoint / subcommand.

Co-authored-by: dtzp555 <dtzp555@gmail.com>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "open-claude-proxy",
-  "version": "3.18.0",
+  "version": "3.19.0",
   "description": "OCP (Open Claude Proxy) — use your Claude Pro/Max subscription as an OpenAI-compatible API for any IDE. Works with Cline, OpenCode, Aider, Continue.dev, OpenClaw, and more.",
   "type": "module",
   "bin": {