fix(peer): refresh settled install state after operations

The follow-up review found a few stale lifecycle edges around local game
transactions. Recovery could sweep active roots, post-operation refreshes
still re-ran full startup recovery, and the UI kept inferring local-only state
from downloaded and installed flags instead of the backend availability.

This updates the peer lifecycle so startup recovery skips active operations,
install/update/uninstall refresh only the affected game after the operation
guard is dropped, and path-changing game-directory updates are rejected while
operations are active. It also removes the dead UpdateGame command, drops the
unused manifest_hash write field while preserving old JSON reads, renames the
internal install-finished event, and carries availability through the DB,
peer summaries, Tauri refreshes, and the React model.

The included follow-up documents record the review source, implementation
decisions, and the remaining FOLLOW_UP_2.md work so later commits can stay
small instead of reopening the completed plan items.

Test Plan:
- git diff --check
- just fmt
- just clippy
- just test

Follow-up-Plan: FOLLOW_UP_PLAN.md

crates/lanspread-compat/src/eti.rs

@@ -1,6 +1,6 @@
 use std::path::Path;
 
-use lanspread_db::db::Game;
+use lanspread_db::db::{AVAILABILITY_LOCAL_ONLY, Game};
 use serde::{Deserialize, Serialize};
 use sqlx::sqlite::{SqliteConnectOptions, SqlitePoolOptions};
 
@@ -63,6 +63,7 @@ impl From<EtiGame> for Game {
             size: (eti_game.game_size * 1024.0 * 1024.0 * 1024.0) as u64,
             downloaded: false,
             installed: false,
+            availability: AVAILABILITY_LOCAL_ONLY.to_string(),
             eti_game_version: None,
             local_version: None,
             peer_count: 0, // ETI games start with 0 peers until peer system discovers them