chore(repo): add Gemini Code Assist config

Author: dackers86

.gemini/config.yaml

@@ -0,0 +1,14 @@
+have_fun: false
+memory_config:
+  disabled: false
+code_review:
+  disable: false
+  comment_severity_threshold: LOW
+  max_review_comments: -1
+  pull_request_opened:
+    help: true
+    summary: true
+    code_review: true
+    include_drafts: true
+ignore_patterns:
+  - "**/node_modules/**"

.gemini/styleguide.md

@@ -0,0 +1,12 @@
+# React Native Firebase Gemini Review Guide
+
+If an `AGENTS.md` file exists at the repository root, follow that guidance first.
+
+If no root `AGENTS.md` file exists, use the guidance below.
+
+## Testing expectations
+
+- Suggest tests when behavior changes or regression risk increases.
+- Prefer focused tests near the changed package rather than broad new coverage.
+- Avoid asking for redundant tests when existing coverage already appears sufficient.
+