feat v1.26.0: state-reflecting icons + 'value instead of an icon' display (issue #3)

- stateIcon(): door/window/garage open-closed, lock locked-unlocked, bulb on;
  custom icons and unavailable/unknown never morph; gated by live_states
- marker display 'value': the measurement (with unit) is the marker body,
  corner badges hidden; numeric fallback chain temp - hum - primary state
- TESTING.md rows, smoke_state_value.mjs, +1 unit test

custom_components/houseplan/manifest.json

@@ -16,5 +16,5 @@
   "issue_tracker": "https://github.com/Matysh/houseplan-card/issues",
   "requirements": [],
   "single_config_entry": true,
-  "version": "1.25.0"
+  "version": "1.26.0"
 }