v1.7.5

Changelog

• ec74716 feat(cli): sondra doctor command, richer root -h, version build-info fallback
• cb6fa2c feat(doctor): preflight checks for tools, presets, templates, and config
• 93d2501 fix(tui): mark httpx/naabu as external binaries so the picker warns if missing
• 1d9110a test(doctor): tool registry and preset-binary mapping