SG-43838 Make Codecov checks advisory with 80% threshold (#1109)

Coverage checks now use informational: true so CI is never blocked
by coverage. Patch and project checks only flag below 80% coverage,
with a 1% threshold on project to suppress noise from small changes.

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

Author: stevelittlefish

codecov.yml

@@ -1,4 +1,21 @@
 
+coverage:
+  status:
+    project:
+      default:
+        # Coverage checks are advisory only - never block CI
+        informational: true
+        # Only flag if overall project coverage drops below 80%
+        target: 80%
+        # Ignore drops of 1% or less (noise from small changes)
+        threshold: 1%
+    patch:
+      default:
+        # Coverage checks are advisory only - never block CI
+        informational: true
+        # Only flag if less than 80% of new/changed lines are covered
+        target: 80%
+
 ignore:
   # ignore generated QT files
   - "**tank/authentication/ui/login_dialog.py"