Normalize dashboard KQL union numeric types

[c-mongan]

Summary

• Cast V2 dashboard query numeric fields before unioning with compatibility fallbacks.
• Keep Log Analytics union output column names stable for duration, token, cost, eval, and recommendation metrics.
• Fix live V2 dashboard KQL against real Logs Ingestion custom tables.

Verification

• node agentops-cli/src/index.js dashboard kql-check --last 24h --require-rows --json
• node agentops-cli/src/index.js product audit --live --last 24h --require-rows --require-visual --visual-evidence .agentops/e2e/20260531T123920Z/iab-visual-evidence/visual-evidence.json --json
• node --test agentops-cli/test/index.test.js --test-name-pattern "dashboard|product audit"
• git diff --check

Note: one earlier live KQL run hit a transient DNS resolution failure for api.loganalytics.io after 29 passing panel checks; immediate rerun passed all 35 checks.