bug: telemetry details URL uses blob/main instead of blob/master (404)

Description

During rtk init -g, the installer prints:

Details: https://github.com/rtk-ai/rtk/blob/main/docs/TELEMETRY.md

The repository's default branch is master, not main, so this URL returns 404. Users who want to read the full telemetry details before accepting are blocked.

Affected files

• src/core/telemetry_cmd.rs (lines 58 and 76)
• src/hooks/init.rs (line 417)

Fix

Replace blob/main/ with blob/master/ in all three locations.

Reproduced on: rtk 0.28.x, Linux (WSL2)