fix(alerting): @Autowired on AlertingMetrics production constructor

Task 29's refactor added a package-private test-friendly constructor
alongside the public production one. Without @Autowired Spring cannot pick
which constructor to use for the @Component, and falls back to searching
for a no-arg default — crashing startup with 'No default constructor found'.

Detected when launching the server via the new docker-compose stack; unit
tests still pass because they invoke the package-private test constructor
directly.

cameleer-server-app/src/main/java/com/cameleer/server/app/alerting/metrics/AlertingMetrics.java

@@ -9,6 +9,7 @@ import io.micrometer.core.instrument.MeterRegistry;
 import io.micrometer.core.instrument.Timer;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.stereotype.Component;
 
@@ -74,6 +75,7 @@ public class AlertingMetrics {
      * Production constructor: wraps the Postgres-backed gauge suppliers in a
      * 30-second TTL cache so Prometheus scrapes don't cause per-scrape DB queries.
      */
+    @Autowired
     public AlertingMetrics(MeterRegistry registry, JdbcTemplate jdbc) {
         this(registry,
              () -> countRules(jdbc, true),