0.19.0: telegram companion hub

[llblab]

Summary

This release reframes pi-telegram as a Telegram companion hub for live Pi sessions, with a product-oriented README, practical feature showcase, and clearer Classic DM vs Threaded Mode onboarding.

It also tightens the Rich Markdown membrane: final assistant/guest answers use native Rich Message delivery, while harness-owned menus, status, diagnostics, queue controls, and settings stay on explicit Telegram HTML/plain rendering. Rich draft previews are now an opt-in progressive enhancement instead of the fresh-install default.

Why

The release reduces onboarding ambiguity and avoids surprising animated draft behavior by making final-only Rich Markdown plus native active status the baseline, while still allowing operators to enable progressive draft previews from Settings.

User-visible behavior

• Root README now explains the product as a Telegram companion console with install/connect flow, operating model, feature showcase, Threaded Mode comparison, safety boundaries, and docs map.
• Telegram Settings exposes Rich drafts so operators can opt into native draft previews.
• Fresh configs preserve final native Rich Markdown replies without sending rich draft preview frames by default.
• Unauthorized guest-query replies use the standard denied-action emoji.

Changed areas

• README.md, AGENTS.md, docs/architecture.md: product/onboarding and Rich Markdown membrane documentation.
• lib/config.ts, lib/menu-settings.ts, index.ts: persisted rich draft preview setting, Settings UI, and preview gate wiring.
• tests/*: config, settings UI, preview gate, and guest denial regressions.
• Package metadata: 0.19.0 release version.

Risk Notes

• Rendering risk is reduced by keeping native Rich Markdown scoped to final model-authored answers and keeping harness UI on explicit HTML/plain.
• Draft preview behavior changes default UX: operators who want progressive draft drawing must enable it in Settings.
• No migration required; missing richDraftPreviews defaults to off.

Validation

• npm run validate — passed
• repo_context_check — passed with 0 warnings/errors