feat: upgrade to Botkit 0.4.0 + Fedify 2.x — republishProfile() works

- Botkit 0.4.0 with Fedify 2.1.2 (no more v1/v2 version mismatch)
- session.republishProfile() replaces our failed broadcast workaround
- Removed parseSemVer import (breaking change: versions are plain strings)
- Single Fedify copy (deduped) — no more dual-package hazard

Author: rmdes