bootstrap: SQLite config, HTTP API on :3000, TCP on :2699, poll loops.
http-api: added serve() so bootstrap doesn't depend on axum directly.
polling: reads data sources from config, polls via http-json adapter,
pushes changed widgets to connected clients.
configure via API, e.g.:
curl -X POST localhost:3000/api/data-sources -H 'Content-Type: application/json' -d '{...}'
curl -X PUT localhost:3000/api/layout -H 'Content-Type: application/json' -d '{...}'
api-types: standalone crate with DTOs (widget, data source, layout, preset)
extracted from http-api. Shared between http-api and future SPA.
thiserror: replaced all manual Display impls with derive macros across
8 crates (config-sqlite, config-memory, tcp-server, tcp-client,
http-json, rss, media, application).
SQLite config store: full ConfigRepository impl with JSON serialization
for mappings, layouts, data source configs. 12 integration tests.
HTTP API: Axum REST endpoints for widgets, data sources, layout, presets.
6 integration tests using tower::oneshot.
Port traits updated to return Send futures for Axum compatibility.
