Fix bare except clauses across connection.py, core.py, abstract_launcher.py, __main__.py

[koteshyelamati]

Several bare except: clauses across the codebase catch BaseException, which includes SystemExit, KeyboardInterrupt, and GeneratorExit. This can prevent clean shutdown and mask bugs.

Changes

pathos/connection.py (lines 127, 135)
Replace bare except: with except Exception: in launch(). The handler re-raises as PipeException — there is no reason to catch interpreter signals.

pathos/core.py (line 265)
Replace bare except: with except Exception: in randomport(). The handler re-raises as TunnelException.

pathos/abstract_launcher.py (line 178)
Replace bare except: pass with except Exception: pass in _launcher_proxy(). Silently swallowing KeyboardInterrupt or SystemExit here would prevent clean process exit.

pathos/__main__.py (lines 78, 87, 104, 120)
Replace bare except: with except IndexError: for sys.argv access. The only exception that can be raised by sys.argv[N] for a missing argument is IndexError — catching everything is overly broad.