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.
Introduce a per-user OOBE state model and hardened launch/elevation handling. Adds OobeStateFile/OobeLaunchDecision models, OobeStateService (persisting %LOCALAPPDATA%/.launcher/state/oobe-state.json), and LauncherExecutionContext to capture elevation and user SID. CommandContext now normalizes/infers launch-source values (normal, postinstall, apply-update, plugin-install, debug-preview) and exposes maintenance checks. LauncherFlowCoordinator propagates richer launcher context details for diagnostics and suppresses OOBE for elevated/maintenance contexts. PluginInstallerService avoids requesting elevation for user-scoped installs and returns a clear error when installation target is outside the current user's LocalAppData. LauncherClient maps and surfaces result codes, UpdateWorkflow and installer invocation now pass explicit --launch-source values, and WelcomeOobeStep persists OOBE completion via the new service. Adds unit tests (CommandContext, OobeStateService, PluginInstallerService), docs/specs/checklists for the contract, and makes internals visible to tests.
