fix: harden Observe telemetry drill-through

[Paulo Lacerda (placerda)]

Summary

• make every Observe table column sortable and add inline metadata-only drill-through for Agents, Models, Tools, and Runs
• scope detail queries to the selected telemetry source and Foundry project while surfacing partial-source failures distinctly from empty results
• correct Overview request/dependency attribution and global p95 computation, and exclude agent/tool spans from Models
• preserve agent/model/source identities so hosted and prompt agents render without misleading Unknown values

Privacy

• drill-through projects operational metadata only; prompts, responses, messages, instructions, and tool payloads are never queried

Validation

• 2456 passed, 1 skipped
• Ruff checks passed
• live App Insights validation covered both prompt and hosted agents, two model deployments, tools, and run correlation