Scaffold kvida-sdk: Vite + TypeScript web client for device settings

First real content in this repo. Runs as a standalone web app (not on
the ESP32 -- Blockly is far too large for the device's flash),
talking to a device already on the LAN via the JSON API kvida-os now
exposes (see kvida-os's transport README, "JSON API" section).

One page: enter a device address, fetch /api/status + /api/mqtt,
edit and save MQTT broker/credentials back via POST /api/mqtt. Proves
the API end-to-end from a real standalone app before any Blockly work
starts.

No framework yet -- kept minimal until the Blockly editor itself is
designed. Verified: npm install/build are clean (no TS errors), and
the dev server was confirmed reachable with the device's CORS headers
allowing cross-origin fetch() calls from it.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,4 @@
+node_modules/
+dist/
+.DS_Store
+*.log