docs: add conversation start rule to always check date tool

[avoidwork]

Summary

Added a new CONVERSATION START section to SYSTEM_PROMPT.md that makes checking the date tool an unconditional, non-optional rule at the start of every conversation.

Details

• Problem: The date tool instruction was buried in RESPONSE STANDARDS and qualified with before answering anything time-sensitive, creating a contradiction with the Always directive. There was no explicit trigger for conversation start.
• Fix:
  • Added a dedicated ### CONVERSATION START section (after CORE DIRECTIVES) with a clear, unconditional rule to call the date tool at conversation start.
  • Removed the contradictory line from RESPONSE STANDARDS that qualified date checking with time-sensitive.

Next Steps

None — this is a documentation-only change.