Sweep the `examples/debugging/` set for basic typing: add `-> None`
to all 16 bare `async def main()`s and annotate the clean
single-line `open_nursery()` bindings as `tractor.ActorNursery`.
Kept to the unambiguous, runtime-safe cases (these breakpoint/crash
demos can't be run headless); the heterogeneous
multi-line/paren-group nursery bindings + `current_actor()` returns
are left for a later pass. Continues the examples-typing bullet in
#472.
(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
Pass explicit `loglevel` to `spawn()` calls in
`test_debugger` tests — required for pexpect
pattern matching now that examples no longer
hard-code log levels.
Also,
- make `expect()` return the decoded `before` str.
- add `start_method` param + fork-backend timeout
slack (+4s) in nested-error test.
- clean up debug examples: drop unused loglevels,
rename `n` -> `an`, fix docstrings, add TODO
comments for tpt parametrize via osenv.
(this commit msg was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
(cherry picked from commit 9431a81d37)