10.5: Add monthly cron example to Automation Opportunity Finder (closes #170)

- Docstring now includes a sample monthly cron job that runs the finder
  on the 1st of each month at midnight, outputting a dated JSON proposal.
- Aligns documentation pattern with other finder scripts (e.g., perf_bottleneck_finder).

Acceptance #170:
  [x] Analyzes: cron jobs, manual steps in docs, repeated patterns
  [x] Identifies: automation candidates
  [x] Output: automation proposals
  [x] Monthly — documented monthly cron usage.

scripts/automation_opportunity_finder.py

@@ -12,6 +12,9 @@ Usage:
     python3 scripts/automation_opportunity_finder.py --hermes-home ~/.hermes
     python3 scripts/automation_opportunity_finder.py --hermes-home ~/.hermes --json
     python3 scripts/automation_opportunity_finder.py --hermes-home ~/.hermes --output proposals.json
+
+Monthly cron (run on the 1st of each month at midnight):
+    0 0 1 * * cd /path/to/compounding-intelligence && python3 scripts/automation_opportunity_finder.py --output proposals/monthly_$(date +\%Y-\%m).json --json --min-confidence 0.5
 """
 
 import argparse