Description

RTK_DISABLED=1 curl ... is still rewritten to RTK_DISABLED=1 rtk curl ... by rtk rewrite. The env var prefix is preserved but never checked — RTK_DISABLED doesn't exist anywhere in the Rust codebase.

Reproduction

rtk rewrite "RTK_DISABLED=1 curl https://example.com"
# Output: RTK_DISABLED=1 rtk curl https://example.com
# Expected: no rewrite (exit 1)

Expected behavior

When a command is prefixed with RTK_DISABLED=1, rtk rewrite should exit 1 (no rewrite).

Fix

Check for RTK_DISABLED=1 prefix in rewrite_command() and skip rewrite.