Add PR-ofiler personal PR activity profiler

[bcullman]

Adds PR-ofiler.ps1, a companion tool to PR-ospector.ps1 for looking back at closed Azure DevOps pull requests where the authenticated user was directly involved.

Unlike PR-ospector, which focuses on open PRs needing attention, PR-ofiler builds a personal activity profile from closed PRs you created, personally approved, or personally commented on. It intentionally excludes passive reviewer-group involvement unless the user actually voted or commented.

Changes:

• Add PR-ofiler.ps1
• Reuse the existing YAML config shape and direct -Org / -Pat usage pattern
• Support filtering by -Days, -Since, -Status, -View, and -MaxPerProject
• Group output into CREATED and INVOLVED sections
• Detect personal approval through direct reviewer entries and votedFor group-member entries
• Detect personal comments from non-system PR thread comments
• Document usage in README.md

Validation:

• PowerShell parse check passed for PR-ofiler.ps1
• No-network smoke test passed for personal identity/vote matching