feat(simplex): groups, native attachments, text batching, auto-accept

Salvage of PR #27978 cherry-picked onto current main, resolving conflicts
with main's intervening SimpleX plugin fixes (resp-envelope normalization,
health-monitor reconnect-churn fix, bare-form DM addressing).

What's new:
- Group support via SIMPLEX_GROUP_ALLOWED (comma-separated IDs or '*');
  inbound items surface chat_id=group:<id> + chat_type=group. Disabled by
  default so a bot in a group doesn't process every member's traffic.
- Inbound files/voice via rcvFileDescrReady (immediate /freceive) deferred
  through _pending_file_transfers, replayed on rcvFileComplete. Voice notes
  -> MessageType.VOICE.
- Native outbound media: send_image (PNG/JPEG + inline thumbnail), send_voice
  (msgContent.type=voice), send_video, send_document. All addressed by numeric
  ID via /_send ... json [...].
- MEDIA:<path> tags in agent replies stripped and dispatched as voice/document.
- Text-burst batching (HERMES_SIMPLEX_TEXT_BATCH_DELAY, default 0.8s).
- Auto-accept contact requests (SIMPLEX_AUTO_ACCEPT, default true).
- Group send path uses structured /_send #<id> json form (the bracket
  #[<id>] form is parsed as display-name lookup and silently drops).

plugin.yaml bumped to 1.1.0; docs updated. All inside plugins/platforms/simplex/
- no core edits.

Co-authored-by: Juraj Bednar <juraj@bednar.io>

plugins/platforms/simplex/plugin.yaml

@@ -1,7 +1,7 @@
 name: simplex-platform
 label: SimpleX Chat
 kind: platform
-version: 1.0.0
+version: 1.1.0
 description: >
   SimpleX Chat gateway adapter for Hermes Agent.
   Connects to a local simplex-chat daemon via WebSocket and relays
@@ -9,7 +9,7 @@ description: >
   SimpleX is decentralised and assigns no persistent user IDs —
   every contact is an opaque internal ID generated at connection
   time, making it one of the most private messengers available.
-author: Mibayy
+author: Mibayy, jooray
 # ``requires_env`` and ``optional_env`` entries are surfaced in the
 # ``hermes config`` UI via the platform-plugin env var injector in
 # ``hermes_cli/config.py``.
@@ -27,6 +27,18 @@ optional_env:
     description: "Allow any contact to talk to the bot (dev only — disables allowlist)"
     prompt: "Allow all contacts? (true/false)"
     password: false
+  - name: SIMPLEX_AUTO_ACCEPT
+    description: "Auto-accept incoming contact requests (default: true)"
+    prompt: "Auto-accept contact requests? (true/false)"
+    password: false
+  - name: SIMPLEX_GROUP_ALLOWED
+    description: >-
+      Comma-separated SimpleX group IDs the bot should participate in, or
+      '*' to allow any group. Omit to ignore group messages entirely
+      (safer default — a bot in a group otherwise processes every
+      member's traffic).
+    prompt: "Allowed group IDs (comma-separated, or '*' for any)"
+    password: false
   - name: SIMPLEX_HOME_CHANNEL
     description: "Default contact/group ID for cron / notification delivery"
     prompt: "Home channel contact/group ID (or empty)"
@@ -35,3 +47,10 @@ optional_env:
     description: "Human label for the home channel (defaults to the ID)"
     prompt: "Home channel display name (or empty)"
     password: false
+  - name: HERMES_SIMPLEX_TEXT_BATCH_DELAY
+    description: >-
+      Quiet-period seconds (default: 0.8) used to concatenate rapid-fire
+      inbound text messages into a single MessageEvent — same pattern as
+      Telegram's text batching.
+    prompt: "Text batch flush delay in seconds (default 0.8)"
+    password: false