claude: expand claude md instructions for testing (#15440)

Expanded some instrucitons in claude.md to cover some annoying patterns
claude falls into

Author: paulpopus

CLAUDE.md

@@ -62,10 +62,13 @@ Payload is a monorepo structured around Next.js, containing the core CMS platfor
 - Use JSDoc for complex functions; add tags only when justified beyond type signature
 - Use `import type` for types, regular `import` for values, separate statements even from same module
 - Prefix booleans with `is`/`has`/`can`/`should` (e.g., `isValid`, `hasData`) for clarity
+- Prefer self describing function and variable names over generic names with comments to explain their purpose
 - Commenting Guidelines
+
   - Execution flow: Skip comments when code is self-documenting. Keep for complex logic, non-obvious "why", multi-line context, or if following a documented, multi-step flow.
   - Top of file/module: Use sparingly; only for non-obvious purpose/context or an overview of complex logic.
   - Type definitions: Property/interface documentation is always acceptable.
+
 - Logger Usage (`payload.logger.error`)
   - Valid: `payload.logger.error('message')` or `payload.logger.error({ msg: '...', err: error })`
   - Invalid: `payload.logger.error('message', err)` - don't pass error as second argument
@@ -146,6 +149,8 @@ Screenshots are saved to `.playwright-mcp/` and displayed inline.
 - If you create a database record in a test, you MUST delete it before the test completes
 - For multiple tests with similar cleanup needs, use `afterEach` to centralize cleanup logic
 - Track created resources (IDs, files, etc.) in a shared array within the `describe` block
+- Do not use conditionals in tests where it can be avoided such as `if else`
+- Do not use `try {} finally {}` in e2e tests; prefer Playwright cleanup hooks (`afterEach`, `afterAll`)
 
 **Example pattern:**