fix: remove context reaper to prevent background tabs from going stale

Background windows stopped updating because the reaper suspended contexts
after ContextSuspendAfter and fully reaped them after ContextTTL. Suspended
contexts had to re-run the page init function from scratch on reconnect,
losing the live-updating experience.

Contexts now live until the browser tab closes (beforeunload beacon) or
the server shuts down. The context map grows indefinitely — no background
reaper.

Removes: startReaper, reapOrphanedContexts, suspend/resume logic,
ContextSuspendAfter/ContextTTL config fields, lastSeenAt/suspended
context fields, and all associated tests.

configuration.go

@@ -1,8 +1,6 @@
 package via
 
 import (
-	"time"
-
 	"github.com/alexedwards/scs/v2"
 	"github.com/rs/zerolog"
 )
@@ -62,16 +60,6 @@ type Options struct {
 	// the embedded NATS server. Ignored when a custom PubSub is configured.
 	Streams []StreamConfig
 
-	// ContextSuspendAfter is the time a context may be disconnected before
-	// the reaper suspends it (frees page resources but keeps the context
-	// shell for seamless re-init on reconnect). Default: 15m.
-	ContextSuspendAfter time.Duration
-
-	// ContextTTL is the maximum time a context may exist without an SSE
-	// connection before the background reaper fully disposes it.
-	// Default: 1h. Negative value disables the reaper.
-	ContextTTL time.Duration
-
 	// ActionRateLimit configures the default token-bucket rate limiter for
 	// action endpoints. Zero values use built-in defaults (10 req/s, burst 20).
 	// Set Rate to -1 to disable rate limiting entirely.