refactor: apply review comments

docs/test-performance-optimization.md

@@ -172,7 +172,7 @@ mix test
 #### CI/CD Integration
 
 - **Standard CI:** Runs `mix test --exclude slow` for faster feedback loops (~6 minutes)
-- **Nightly Builds:** Separate pipeline runs daily and executes `mix test --only slow` (~1.3 minutes)
+- **Nightly Builds:** Separate pipeline runs daily and executes `mix test` (all tests, including slow) for comprehensive coverage (~7.4 minutes)
 - **Pre-Merge:** Full test suite (`mix test`) runs before merging to main
 - **Manual Execution:** Can be triggered via Drone CLI or Web UI
 
@@ -535,13 +535,18 @@ mix test test/mv_web/member_live/index_member_fields_display_test.exs --slowest
 - Execution time: ~6 minutes
 - Command: `mix test --exclude slow` or `just test-fast`
 
-**Slow/Nightly Tests:**
-- Tests tagged with `@tag :slow` (25 tests)
+**Slow Tests:**
+- Tests tagged with `@tag :slow` or `@describetag :slow` (25 tests)
 - Low risk, >1 second execution time
-- UI/Display tests, workflow details, edge cases
+- UI/Display tests, workflow details, edge cases, performance tests
 - Execution time: ~1.3 minutes
 - Command: `mix test --only slow` or `just test-slow`
-- Run in nightly CI builds
+- Excluded from standard CI runs
+
+**Nightly CI Builds:**
+- Runs all tests (`mix test`) for comprehensive coverage
+- Execution time: ~7.4 minutes
+- Ensures full test coverage including slow/performance tests
 
 **All Tests:**
 - Includes both fast and slow tests
@@ -692,13 +697,13 @@ A: Monitor for 2-3 months. If no seeds-related bugs appear that would have been
 A: Consider running the full test suite (including slow tests) before major releases. Daily development uses the optimized suite.
 
 **Q: How do I add a new performance test?**  
-A: Tag it with `@tag :slow` or `@moduletag :slow`. See "Performance Test Guidelines" section above.
+A: Tag it with `@tag :slow` for individual tests or `@describetag :slow` for describe blocks. Use `@describetag` instead of `@moduletag` to avoid tagging unrelated tests. Include measurable performance assertions (query counts, timing with tolerance, etc.). See "Performance Test Guidelines" section above.
 
 **Q: Can I run slow tests locally?**  
 A: Yes, use `just test-slow` or `mix test --only slow`. They're excluded from standard runs for faster feedback.
 
 **Q: What is the "nightly suite"?**  
-A: The "nightly suite" refers to tests tagged with `@tag :slow`. We use a single tag (`:slow`) for both performance tests and tests suitable for nightly execution. All tests tagged with `:slow` are excluded from standard runs and can be executed in nightly CI builds. 
+A: The "nightly suite" refers to the nightly CI pipeline that runs **all tests** (`mix test`), including slow tests. Tests tagged with `@tag :slow` or `@describetag :slow` are excluded from standard CI runs for faster feedback, but are included in the nightly full test suite for comprehensive coverage. 
 
 **Q: Which tests should I tag as `:slow`?**  
 A: Tag tests with `@tag :slow` if they: (1) take >1 second, (2) have low risk (not critical for catching regressions), and (3) test UI/Display/Formatting or workflow details. See "Test Tagging Guidelines" section for details.