feat: unified self-upgrade (source/release/service) + /self-upgrade command + /models command with inline keyboard

[chinkan]

Summary

Two major improvements to RustFox runtime management:

1. Unified Self-Upgrade

The self_update_to_branch tool has been replaced with a unified self_upgrade() that auto-detects the deployment mode and handles all three paths:

Mode	Detection	Behavior
Source	Cargo.toml found near binary	git fetch → checkout → pull → cargo build --release → spawn new binary
Release binary	No Cargo.toml	Downloads latest GitHub release via self_update crate → atomic binary swap
Service	systemd/launchd service file exists	Same as above + cargo install --path . + rustfox --service install rerender + systemctl restart

New user-facing command: /self-upgrade [branch] — bypasses the LLM, shows inline per-step progress via live edit_message_text, then auto-restarts.

Improved LLM tool: self_upgrade(branch, mode) — renamed from self_update_to_branch, adds mode param (auto/source/release), properly sets restart_pending flag for deferred restart.

2. /models Command

Browse and switch OpenRouter models at runtime without restart:

Input	Behavior
/models	Shows current model + usage help
/models <exact-id>	Validates against API, saves to config.toml, hot-reloads
/models <keyword>	Fuzzy searches id and name fields — top 5 shown as inline keyboard buttons

Inline keyboard: Search results show tappable buttons (callback query handler saves model + edits message). Cancel button included. set_model() persists to config.toml via TOML round-trip and updates an in-memory RwLock — next LLM call picks up the new model immediately.

Technical Changes

File	Change
Cargo.toml	Added self_update = \0.44\
src/learning.rs	New self_upgrade(), restart_bot(), is_service_installed(), detect_deployment_mode(), find_project_root()
src/agent.rs	restart_pending: AtomicBool, current_model: RwLock<String>, config_path, set_model(), updated chat_completion call, renamed dispatch arm
src/llm.rs	ModelInfo struct + fetch_models()
src/tools.rs	Renamed self_update_to_branch → self_upgrade with mode param
src/platform/telegram.rs	/self-upgrade command (inline progress), /models command (smart search + inline keyboard), callback query handler, restart check
src/main.rs	Pass config_path to Agent
scripts/services/rustfox.service.template	Restart=on-failure → Restart=always

Verification

• cargo check ✅
• cargo clippy -- -D warnings ✅
• cargo fmt --all -- --check ✅
• cargo test — 371 unit + 14 integration tests, all pass ✅