narrow-bare-rescue

# Narrow Bare Rescue Turn `rescue _ -> fallback` into `rescue _ in [ExceptionType1, ExceptionType2] -> fallback` so programmer bugs propagate while known failure modes stay handled. ## Why this matters Bare rescues (`rescue _ ->`, `rescue e ->` — any form without an `in` clause) swallow **every** exception, including `UndefinedFunctionError` from typos, `KeyError` from misspelled map keys, and `CompileError` from bad HEEx templates. The symptom isn't a stack trace — it's a silent `{:error, :generic}` or a `nil` fallback. Bugs that should surface in tests or error reporters become quiet degradations. The Erlang [Secure Coding Guide](https://www.erlang.org/doc/system/secure_coding.html) makes the same case at the BEAM level — rule **LNG-002** ("Do Not Use `catch`") warns that the legacy catch-all form conflates normal returns, throws, and errors. Bare `rescue` in Elixir is the direct analogue. ## Iron Laws 1. **Never leave `rescue _ ->` or `rescue e ->` without an `in` clause.** Every rescue must list exact exception types. The Credo check enforces this after cleanup lands. 2. **Cover every exception the code path can actually raise.** Narrowing that drops a real exception is a behavioral regression — trace each call in the body before committing. 3. **Never include programmer-bug exceptions in the list.** `UndefinedFunctionError`, `CompileError`, `BadFunctionError`, and `BadArityError` must propagate. 4. **Use `reraise e, __STACKTRACE__`, never `reraise e, []`.*...