Enhancement: Settings Soft apply for Local process remount without rebuild

[Unthred]

Problem

HardRestart Settings still use StopAll → StartActive → BuildAsync when StartOnLaunch is enabled. Some Local changes need a process/watcher remount but not a full rebuild (e.g. RunMode, RootFolder/ProjectFile after a clean stop, WatchExcludeSegments remount).

Proposal

Add a restart-without-build (or remount-watcher) apply path distinct from cold launch, and optionally Soft-refresh watch excludes (set/replace, not add-only).

Out of scope for #87

#87 SoftRuntime-classifies policy knobs read live via UpdateDefinition (RunTests, restart flags, BuildControlMode, etc.) and keeps HardRestart only for true process/watcher identity. This issue tracks finer-grained apply.

Acceptance

• Documented apply plan for remount-without-rebuild
• Watch excludes can update live without Local rebuild when remount is implemented
• HardRestart path still used when a build is genuinely required