fix: Clear the initialized condition state when the card is not usable (#2646)

The `initialized` state (used in conditions/triggers) was written once
and never cleared, so it meant "has this card ever been initialized"
while everything reading it took it as "is this card usable now". Home
Assistant takes a card off the page and puts it back whenever its
dashboard tab is left and returned to, so the card initialized again
while the state claimed it was initialized throughout: `trigger:
initialized` fired once per card rather than once per startup, and
automations were dropped in between.

The card lifecycle is now an explicit state machine (`SessionManager`),
the only writer of `initialized`, which separates a card that is
starting up from one initializing part of itself again while it runs. A
new `ever` parameter (conditions/triggers) selects the old latched
behaviour.

`remote_control` uses that parameter to keep its two camera priorities
correct under repeated starts. With `camera_priority: entity` the card
now re-reads the entity every time it starts, so a camera selected while
the card was away is picked up on return. With `camera_priority: card`
the card writes the entity on its first start only, unchanged, since
repeating that write would overwrite a camera the user had selected.

Closes: #2642


BREAKING CHANGE: `condition: initialized` is now `false` whenever the
card is not usable, and `trigger: initialized` fires each time the card
starts up rather than only the first time. Set `ever: true` on either to
keep the previous behaviour.

tests/browser/mounted-card.ts

@@ -311,6 +311,36 @@ export class MountedCard {
     this.card.hass = this._hass.getHASS();
   }
 
+  /**
+   * Drop or restore the connection to Home Assistant, then hand the card the
+   * resulting `hass`.
+   */
+  public setConnected(connected: boolean): void {
+    this._hass.setConnected(connected);
+    this.card.hass = this._hass.getHASS();
+  }
+
+  /**
+   * Give the card a new configuration.
+   */
+  public setConfig(config: RawAdvancedCameraCardConfig): void {
+    this.card.setConfig(config);
+  }
+
+  /**
+   * Take the card off the page.
+   */
+  public detach(): void {
+    this.card.remove();
+  }
+
+  /**
+   * Put the card back on the page.
+   */
+  public attach(): void {
+    this._container.append(this.card);
+  }
+
   /**
    * Resolves once the card itself has rendered, which says nothing about the
    * elements beneath it.