v0.0.28: BotFather-only registration, per-instance bot toggle, docs update

Security:
- Bot registration restricted to BotFather (requires botfather_token)
- Direct POST /v1/bot/register without BotFather auth → rejected

Deploy:
- systemd service reads /home/warzone/server.env for EXTRA_ARGS
- deploy/warzone-server.env.mequ: no bots (default)
- deploy/warzone-server.env.kh3rad3ree: --enable-bots
- setup.sh copies per-hostname env file

Docs updated:
- LLM_HELP.md: BotFather flow, plaintext bot messaging, E2E option, bridge
- LLM_BOT_DEV.md: botfather_token requirement, E2E mode, bridge section
- BOT_API.md: full BotFather flow, ownership, numeric IDs, webhook delivery
- SERVER.md: --enable-bots flag, per-instance config, bot system section
- USAGE.md: bot messaging, BotFather, bridge tool

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

warzone/Cargo.toml

@@ -9,7 +9,7 @@ members = [
 ]
 
 [workspace.package]
-version = "0.0.27"
+version = "0.0.28"
 edition = "2021"
 license = "MIT"
 rust-version = "1.75"