Introduce support for choosing and resolving the application's data root (system user dir vs. portable app folder). Adds DataLocationConfig model, DataLocationResolver (load/save/resolve/migrate), a UI prompt (DataLocationPromptWindow) and an OOBE step (DataLocationOobeStep) to let users pick and optionally migrate existing data. Wire the chosen data root into the launcher flow and host launch plan (forwarded via --data-root and LMD_DATA_ROOT), and add AppDataPathProvider to let runtime services read the effective data root (initialized in Program.Main). Update various services (logging, settings, DB, plugin/market, startup registry, etc.) to use the new provider/resolver and register the config type in the JSON context. This enables portable installs, safe migration, and runtime overrides via CLI or environment variable.
Add HostLaunchPlan/HostLaunchPlanBuilder to encapsulate host path, package root, working dir, forwarded args and env; add unit tests for builder. Refactor LauncherFlowCoordinator to use HostLaunchPlan when starting hosts, improve IPC handling and startup logic (shorter soft/hard timeouts, more frequent reconnects and shell status polling, activation recovery via existing host). Move argument formatting and environment setup into the plan, include package/working/args metadata in start attempts. Update Commands to prefer ProcessPath for launcher base directory. App and Program: start single-instance activation listener earlier and harden ActivateMainWindow to handle shell initialization state and return richer activation status codes. SingleInstanceService: signal listener readiness (ManualResetEventSlim) and wait briefly when starting, and dispose it. Various logging and minor error handling improvements.
