fix: restore beforeExit handler for version commands and add comprehensive telemetry debug logging

[eablack]

Summary

This PR fixes a regression where telemetry was not being sent for version/help commands, and adds comprehensive debug logging throughout the telemetry system to improve observability.

Key Changes:

1. Restored beforeExit handler with deduplication mechanism to capture telemetry for commands that don't trigger the postrun hook (e.g., version, --version, -v)
2. Added comprehensive debug logging that shows telemetry status (enabled/disabled) and the action being taken at each checkpoint
3. Improved disabled messaging to include the reason for disabling (e.g., DISABLE_TELEMETRY=true, Windows platform requires ENABLE_WINDOWS_TELEMETRY=true)
4. Optimized redundant checks in bin/run.js to call isTelemetryEnabled() once instead of twice

Problem:

When the telemetry architecture was refactored in commit c13074d, the beforeExit handler was removed to avoid duplicate sends. This caused version/help commands to stop sending telemetry entirely because they don't trigger the postrun hook (oclif handles them specially).

Solution:

• Added telemetrySent flag to TelemetryGlobal interface
• Postrun hook sets this flag after sending telemetry
• beforeExit handler only sends if the flag is NOT set (preventing duplicates)
• Added contextual debug logging at every telemetry checkpoint

Type of Change

Patch Updates (patch semver update)

• fix: Bug fix

Testing

Notes:
Set DEBUG=heroku:analytics to see telemetry debug output.

Steps:

1. Test version command: DEBUG=heroku:analytics heroku version - should see telemetry sent via beforeExit
2. Test regular command: DEBUG=heroku:analytics heroku apps:info --app myapp - should see telemetry sent via postrun (no duplicate from beforeExit)
3. Test disabled telemetry: DEBUG=heroku:analytics DISABLE_TELEMETRY=true heroku version - should see clear "disabled" messages with reasons
4. On Windows without ENABLE_WINDOWS_TELEMETRY=true: Should see appropriate disabled message
5. Verify no duplicate sends by checking debug output shows only one "Sending telemetry" message per command

Screenshots (if applicable)

N/A - Debug logging output only

Related Issues

https://gus.lightning.force.com/lightning/r/ADM_Work__c/a07EE00002XtZcuYAF/view

[tlowrimore-heroku]

LGTM!