perf: align ps process-table cache TTL with the 2s consumer window

The runtime process table is read through a module-level executor cache (1s TTL)
but its consumers rebuild on a 2s snapshot-cache cadence and fire constantly during
a launch (every team file change invalidates a per-team snapshot). A 1s table TTL
is shorter than the 2s read cadence, so 'ps -ax' was re-spawned on essentially every
consumer rebuild for no freshness benefit -- a top main-thread cost in the warm
launch profile (~5-8%). Raise the table TTL to 2s to match the consumer window so
the spawn coalesces to at most once per consumer cycle.

Safe: liveness is identity-matched (team+agent+command), not bare-PID, and OpenCode
host cleanup re-validates each PID against live state before killing, so a ~2s-stale
table cannot cause a wrong liveness verdict or an unsafe kill -- it only widens an
already-tolerated display-staleness window by ~1s. No test asserts the TTL value.

src/features/tmux-installer/main/infrastructure/runtime/TmuxPlatformCommandExecutor.ts

@@ -40,11 +40,15 @@ export interface RuntimeProcessTableRow {
  * very frequently (every team file change invalidates their per-team snapshot
  * caches), so without throttling here the main process spawns `ps` dozens of
  * times per second while a team runs. Those callers already tolerate ~2s
- * staleness via their own snapshot caches, and the OS process table changes
- * negligibly within a second, so a 1s window collapses the spawn storm without
- * affecting liveness correctness.
+ * staleness via their own snapshot caches (AGENT_RUNTIME_SNAPSHOT_CACHE_TTL_MS),
+ * so caching the table for a SHORTER window than the consumers read it just
+ * re-spawns `ps` on every consumer rebuild for no freshness benefit. Match the
+ * 2s consumer window to collapse those redundant spawns: liveness verdicts are
+ * identity- (team+agent+command) not bare-PID matched, and OpenCode host cleanup
+ * re-validates each PID against live state before acting, so a ~2s-stale table
+ * cannot cause a wrong liveness call or an unsafe kill.
  */
-const RUNTIME_PROCESS_TABLE_CACHE_TTL_MS = 1_000;
+const RUNTIME_PROCESS_TABLE_CACHE_TTL_MS = 2_000;
 
 interface RuntimeProcessTableCacheEntry {
   rows: RuntimeProcessTableRow[];