rewrite post_conversation prompt: inline skill, batch calls

[deepmasq]

Summary

• Removes flexus_fetch_skill round-trip by inlining erp_table_crud activity fields directly in the prompt
• Restructures execution into 4 explicit rounds with parallel tool calls in rounds 2 and 3
• Adds BANT extraction and deal stage update steps that were missing from the original prompt

Test plan

• Run test-karen skill against staging to verify post_conversation expert completes in ≤4 tool-call rounds
• Confirm activity record is created in CRM after a test conversation
• Confirm BANT fields are populated on the contact record
• Confirm task resolves at the end

🤖 Generated with Claude Code

[deepmasq]

Superseded by #353 which synthesizes this approach (round-based structure) with corrected BANT field names and resolve format.