docs: run tests with an in-memory DATABASE_URL

The docs said tests need BASE_PATH in .env. The full suite (lib, bin and
integration tests) passes with no .env and no BASE_PATH; the only thing
it needs is DATABASE_URL, and ":memory:" works. Without it, DB-backed
tests such as reels::tests::reel_capture_preserves_owner_defaults panic
with "DATABASE_URL must be set".

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

CLAUDE.md

@@ -25,14 +25,14 @@ RUST_LOG=debug cargo run
 
 ### Testing
 ```bash
-# Run all tests (requires BASE_PATH in .env)
-cargo test
+# Run all tests. DATABASE_URL is the only env var the suite needs; no .env required
+DATABASE_URL=":memory:" cargo test
 
 # Run specific test
-cargo test test_name
+DATABASE_URL=":memory:" cargo test test_name
 
 # Run tests with output
-cargo test -- --nocapture
+DATABASE_URL=":memory:" cargo test -- --nocapture
 ```
 
 ### Database Migrations
@@ -664,7 +664,7 @@ Module map:
 
 ## Testing Patterns
 
-Tests require `BASE_PATH` environment variable. Many integration tests create temporary directories and files.
+Tests need `DATABASE_URL` set; `DATABASE_URL=":memory:"` is enough to run the whole suite without a `.env` (otherwise DB-backed tests such as `reels::tests::reel_capture_preserves_owner_defaults` panic with `DATABASE_URL must be set`). Many integration tests create temporary directories and files.
 
 When testing database code:
 - Use in-memory SQLite: `DATABASE_URL=":memory:"`

README.md

@@ -243,3 +243,10 @@ unset.
   populated retroactively) [default: `2000`]. Errors don't burn the cap;
   only successful hashes count.
 
+## Testing
+`DATABASE_URL` is the only environment variable the test suite needs, and an
+in-memory SQLite database works, so no `.env` is required:
+
+```bash
+DATABASE_URL=":memory:" cargo test
+```