Improve testing notes in CLAUDE.md (#1970)

- Clarify that `make test` compiles and loads the extension automatically,
  so `make all` and `make install` are not needed before running tests
- Recommend the `.log` file as the starting point for debugging failed
  tests, as it contains all intermediate output in one place

Author: GromNaN

.claude/CLAUDE.md

@@ -40,7 +40,10 @@ make test TESTS=tests/path/to/test.phpt
 make test TESTS="tests/path/to/pattern*.phpt"
 ```
 
-For failed tests, all intermediate files (e.g. expected output, actual output, diff) are left alongside the test file. This is helpful for debugging purposes. 
+`make test` compiles the extension and loads it automatically — no need to run `make all` or `make install` first.
+
+For failed tests, all intermediate files (e.g. expected output, actual output, diff) are left alongside the test file.
+The `.log` file contains everything in one place and is the recommended starting point for debugging.
 
 Key environment variables for testing:
 - `MONGODB_URI` – connection string (default: `mongodb://127.0.0.1/`)