feat(welcome-agent): proactive context-aware integration suggestions #995

Description

Follow-up from #885. The welcome agent has the ability to generate connection links but only does so when the user explicitly asks. The agent should proactively suggest relevant integrations based on what the user says during the discovery phase.

Current behavior

The agent never proactively suggests integrations based on user context — it only generates connection links when the user explicitly requests one.

Expected behavior

Based on what the user shares about their workflow, the agent should proactively suggest and offer connection links for relevant integrations:

• "I manage my work" → Notion, Gmail, Google Calendar, Slack
• "I do sales" → LinkedIn, Gmail, CRM integrations
• "I'm a developer" → GitHub, Slack, Discord
• "I want to stay connected" → WhatsApp, Telegram, Discord, iMessage

After connecting one, acknowledge it and suggest the next natural one.