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>

README.md

@@ -961,6 +961,7 @@ Then restart OCP. At boot you will see:
 - **Callers see no API change.** The response is a normal OpenAI completion object or chunked SSE — identical wire format.
 - **No real token streaming.** TUI-mode buffers the full response then replays it as chunked SSE. You will see a delay then the complete response rather than real-time tokens.
 - **Cache and singleflight work normally.** TUI-mode writes the buffered response to the cache on success; cache-hits skip the interactive turn entirely.
+- **The host's `CLAUDE.md` / auto-memory is never injected.** OCP is a proxy — the proxied client (OpenClaw / your IDE) owns its own context and memory. TUI-mode always runs `claude` with `CLAUDE_CODE_DISABLE_CLAUDE_MDS` + `CLAUDE_CODE_DISABLE_AUTO_MEMORY`, so a `CLAUDE.md` on the OCP host can never leak into proxied turns (verified live; see #4). Built-in tool schemas + the interactive system prompt remain (the inherent ~20–35K context floor of interactive mode); MCP is hard-disabled.
 - **Default path unchanged.** Unset `CLAUDE_TUI_MODE` and restart → `callClaude` / `callClaudeStreaming` are used again, byte-for-byte identical to today.
 
 ### Kill-switch