Add retained state, Data Controller, and Resource lifecycle applications under examples, with paired guidance and public-path interaction tests.
Verified with make check (57 behavior tests and 5 docs tests), make load, byte compilation, checkdoc, and GUI width checks at 784px body width.
Keep ETAF's framework and data responsibilities unchanged while pointing development, documentation, and test load paths at the new standalone Ebox package.
Keep View, Component, Runtime, reactive, Context, Resource, Behavior, Action, and Data in one core package; add the Grid Host lowering path; remove bundled UI and Playground copies; and document the independent package graph.
Deliver the unified View and Component model with retained Runtime, reactive scopes, Context, Behaviors, events, Actions, styles, Resources, Data, official UI Components, and Playground examples.\n\nVerification: make check and make load pass in the independent repository; sibling Ebox core tests pass 544/544.
Implement the P0 View grammar, expr bridge, stateless view Components, and Ebox mount path in a new independent package. Include bilingual architecture and implementation documents plus contract tests.
