fix: remove context reaper to prevent background tabs from going stale (#4)

docs/getting-started.md

@@ -66,7 +66,6 @@ v.Config(via.Options{
     Plugins:         []via.Plugin{MyPlugin},
     SessionManager:  sm,
     PubSub:          customBackend,
-    ContextTTL:      60 * time.Second,
     ActionRateLimit: via.RateLimitConfig{Rate: 20, Burst: 40},
 })
 ```
@@ -83,7 +82,6 @@ v.Config(via.Options{
 | `DatastarContent` | (embedded) | Custom Datastar JS bytes |
 | `DatastarPath` | `"/_datastar.js"` | URL path for the Datastar script |
 | `PubSub` | embedded NATS | Custom PubSub backend. Replaces the default NATS. See [PubSub and Sessions](pubsub-and-sessions.md) |
-| `ContextTTL` | `30s` | Max time a context survives without an SSE connection before cleanup. Negative value disables the reaper |
 | `ActionRateLimit` | `10 req/s, burst 20` | Default token-bucket rate limiter for action endpoints. Rate of `-1` disables limiting |
 
 ## Static Files

docs/state-and-interactivity.md

@@ -14,7 +14,7 @@ Browser hits page → new Context created → init function runs → HTML render
                         action fires → signals injected from browser → handler runs → Sync() → DOM patched
 ```
 
-The context is disposed when the SSE connection closes (tab close, navigation away, network loss). A background reaper also cleans up contexts that never establish an SSE connection within `ContextTTL` (default 30s).
+The context lives until the browser tab closes (detected via a `beforeunload` beacon) or the server shuts down. There is no background reaper — contexts persist across temporary SSE disconnections so backgrounded tabs resume seamlessly.
 
 During [SPA navigation](routing-and-navigation.md#spa-navigation), the context itself survives — only page-level state (signals, actions, fields, intervals, subscriptions) is reset. The SSE connection persists.