Simplify HomeAssistantWebSocket and raise on connection errors (#6553)

* Raise HomeAssistantWSError when Core WebSocket is unreachable

Previously, async_send_command silently returned None when Home Assistant
Core was not reachable, leading to misleading error messages downstream
(e.g. "returned invalid response of None instead of a list of users").

Refactor _can_send to _ensure_connected which now raises
HomeAssistantWSError on connection failures while still returning False
for silent-skip cases (shutdown, unsupported version). async_send_message
catches the exception to preserve fire-and-forget behavior.

Update callers that don't handle HomeAssistantWSError: _hardware_events
and addon auto-update in tasks.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* Simplify HomeAssistantWebSocket command/message distinction

The WebSocket layer had a confusing split between "messages" (fire-and-forget)
and "commands" (request/response) that didn't reflect Home Assistant Core's
architecture where everything is just a WS command.

- Remove dead WSClient.async_send_message (never called)
- Rename async_send_message → _async_send_command (private, fire-and-forget)
- Rename send_message → send_command (sync wrapper)
- Simplify _ensure_connected: drop message param, always raise on failure
- Simplify async_send_command: always raise on connection errors
- Remove MIN_VERSION gating (minimum supported Core is now 2024.2+)
- Remove begin_backup/end_backup version guards for Core < 2022.1.0
- Add debug logging for silently ignored connection errors

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* Wait for Core to come up before backup

This is crucial since the WebSocket command to Core now fails with the
new error handling if Core is not running yet.

* Wait for Core install job instead

* Use CLI to fetch jobs instead of Supervisor API

The Supervisor API needs authentication token, which we have not
available at this point in the workflow. Instead of fetching the token,
we can use the CLI, which is available in the container.

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

.github/workflows/builder.yml

@@ -323,6 +323,35 @@ jobs:
           docker logs --tail 50 hassio_supervisor
           exit 1
 
+      # Wait for Core to come up so subsequent steps (backup, addon install) succeed.
+      # On first startup, Supervisor installs Core via the "home_assistant_core_install"
+      # job (which pulls the image and then starts Core). Jobs with cleanup=True are
+      # removed from the jobs list once done, so we poll until it's gone.
+      - name: Wait for Core to be started
+        run: |
+          echo "Waiting for Home Assistant Core to be installed and started..."
+          timeout=300
+          elapsed=0
+
+          while [ $elapsed -lt $timeout ]; do
+            jobs=$(docker exec hassio_cli ha jobs info --no-progress --raw-json | jq -r '.data.jobs[] | select(.name == "home_assistant_core_install" and .done == false) | .name' 2>/dev/null)
+            if [ -z "$jobs" ]; then
+              echo "Home Assistant Core install/start complete (took ${elapsed}s)"
+              exit 0
+            fi
+
+            if [ $((elapsed % 15)) -eq 0 ]; then
+              echo "Core still installing... (${elapsed}s/${timeout}s)"
+            fi
+
+            sleep 5
+            elapsed=$((elapsed + 5))
+          done
+
+          echo "ERROR: Home Assistant Core failed to install/start within ${timeout}s"
+          docker logs --tail 50 hassio_supervisor
+          exit 1
+
       - name: Check the Supervisor
         run: |
           echo "Checking supervisor info"