Move --batch branches out of main.py

[rolandwalker]

Description

Move --batch branches out of main.py, creating a main_modes directory, into which other modes can be moved.

It might be considered very rough to pass the entire MyCli and CliArgs instances as arguments, but this is at least a step to breaking up the large main.py file into logical sections.

Some comments regarding statement count were removed, and exceptions are handled differently, but no functional change is intended.

Relevant tests are moved to test/pytests/test_main_modes_batch.py, and new tests are added for greater coverage.

main_modes/ might not be the best name. main_dispatch? I didn't want to write out main_execution_paths.

Checklist

• I added this contribution to the changelog.md file.
• I added my name to the AUTHORS file (or it's already there).
• To lint and format the code, I ran

  uv run ruff check && uv run ruff format && uv run mypy --install-types .

[github-actions]

Codex Review

1. High: unhandled query/runtime exceptions now escape batch mode and can produce traceback instead of controlled CLI exit
   In mycli/main_modes/batch.py, dispatch_batch_statements() catches Exception, prints, then re-raises. But callers only catch narrow exception sets:

   • main_batch_with_progress_bar() catches ValueError|StopIteration|IOError|OSError
   • main_batch_without_progress_bar() catches ValueError|StopIteration|IOError|OSError
   • main_batch_from_stdin() catches only ValueError

   A RuntimeError (or most DB/query exceptions) from run_query() now bypasses these handlers. Before this refactor, the inline code in main.py exited immediately on any exception.
   Action: either catch Exception in each main_batch_* function (and return 1), or stop re-raising in dispatch_batch_statements and return a status consistently.

2. Medium: destructive-confirmation TTY failures can now be uncaught in stdin batch path
   dispatch_batch_statements() re-raises OSError/IOError when /dev/tty cannot be opened. main_batch_from_stdin() does not catch those (line 138), so stdin-driven batch mode can crash with traceback instead of a clean error exit.
   Action: include OSError|IOError (or Exception) in main_batch_from_stdin() handling.

3. Missing test coverage for the above regression
   Current tests validate dispatch_batch_statements re-raises (test_dispatch_batch_statements_sleeps_and_reraises_query_errors) but do not assert top-level CLI behavior when dispatch raises non-IO exceptions in each mode.
   Action: add tests that simulate dispatch_batch_statements raising RuntimeError (and TTY OSError) through:

   • main_batch_with_progress_bar
   • main_batch_without_progress_bar
   • main_batch_from_stdin
     and assert clean nonzero exit with error message, no uncaught exception.

Could not run the test suite locally because uv is not installed in this environment (uv: command not found).