azd tool: add custom telemetry for tool management product insights

## Problem

The generic telemetry middleware tracks command-level usage and errors, but there's no custom telemetry to answer key product questions:

- Which tools are most/least installed across users?
- Which tools do users choose to install vs skip?
- What install strategies are being used (brew vs winget vs npm)?
- Success/failure rate per tool and per strategy?
- In first-run, do users accept or decline? Which tools do they select?

## Proposed Solution

Add span attributes to telemetry events for:
- Tool IDs detected/installed/skipped
- Install strategy used per tool
- Install outcome (success/failure) with error category
- First-run accept/decline and tool selection

## Context

Raised by @vhvb1989 in PR #7450 review. Deferred to post-merge to keep the current PR focused on functionality.

## Related

- PR #7450
- Issue #7845 (Epic A: Core Command Group)