feat(tui+release): persist vitest memory guard, aggregate root CHANGELOG, lockstep all packages

TUI: vitest memory-guard threshold and on/off toggle now persist to
global settings (vitestAutoKillEnabled / vitestKillThresholdPct), so
they survive dashboard restarts. Stats panel shows the system-memory
used percentage next to used/free. Utilities panel exposes [+/-] to
adjust the threshold in 5% steps (50–99%).

Release: scripts/release.mjs auto-syncs a root CHANGELOG.md aggregated
from every packages/*/CHANGELOG.md, grouped by version with one
sub-block per package.

Versioning: all private @fusion/* packages joined the changesets fixed
group with the public cli + cli-alias and were aligned to 0.2.5, so
every release bumps every package and produces per-package CHANGELOG
entries that the aggregator picks up.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/core/src/settings-schema.ts

@@ -52,6 +52,9 @@ export const DEFAULT_GLOBAL_SETTINGS = {
   // Dashboard session state (persisted to global settings for PWA/offline restore)
   dashboardCurrentNodeId: undefined,
   dashboardCurrentProjectIdByNode: undefined,
+  // Dashboard TUI memory guard
+  vitestAutoKillEnabled: true,
+  vitestKillThresholdPct: 90,
 } satisfies CompleteSettings<GlobalSettings>;
 
 /** Default values for project-level settings. */