fix: Zulip attachment handling — event attachments + all file types

hermes-zulip-plugin (Tanko/Mumuni):
  - Add _extract_event_attachments() to handle message.attachments from
    Zulip UI file uploads (previously only inline markdown links worked)
  - Add shared _cache_attachment() method for images/audio/documents
  - Refactor _extract_inline_media() to use _cache_attachment()
  - Fix connect() signature for hermes-agent 0.18.0 compat (add is_reconnect)

pi-zulip-extension (Abiba):
  - Extend attachment handling beyond images only: text files (decoded
    inline), PDFs (pdftotext extraction), binary files (metadata)
  - 50K char cap on text/PDF extraction to prevent context flooding
  - Classify attachments by extension (image/text/pdf/binary)

pi-mcp-extension (Abiba):
  - Detect bridge-side text truncation (… ellipsis marker)
  - Rebuild relay message display from structuredContent when truncated
  - Add rebuildRelayTextFromStructuredContent() helper

Config:
  - Add ZULIP_ROLE=router to ecosystem.abiba.config.cjs (was missing)

pi-zulip-extension/config.yaml.example

@@ -0,0 +1,24 @@
+# pi Zulip extension — Abiba configuration (flat format for custom parser)
+# Deploy to: ~/.pi/agent/extensions/config.yaml
+
+zulip.site: https://chat.sysloggh.net
+zulip.email: abiba-bot@chat.sysloggh.net
+zulip.api_key: cKTDMZAPW08dk3zl05sStzO7HRztzyn8
+zulip.stream: agent-hub
+zulip.all_bots_user_id: 20
+
+agent.name: abiba
+agent.display_name: Abiba
+agent.zulip_bot_name: abiba-bot
+agent.owner_email: jerome@sysloggh.com
+agent.private_topic: abiba
+
+health_port: 9200
+
+monitoring.health_endpoint_enabled: true
+monitoring.log_level: info
+
+error_handling.timeout_seconds: 30
+error_handling.retry_count: 3
+error_handling.retry_delay_seconds: 5
+error_handling.graceful_message: "Abiba encountered an error processing your request. Please try again later."