fix: replace bare except with except KeyError in translator.py

[koteshyelamati]

Bare except: clauses catch BaseException, including SystemExit and KeyboardInterrupt.

In translator.py, the bare except: wraps a dict cache lookup — the only possible exception is KeyError (cache miss). Using except KeyError: is the precise fix and makes the intent clearer.

[koteshyelamati]

Extended this PR with fixes for bare except: in 4 constructor files:

• jsarraybuffer.py, jsfloat32array.py, jsint8array.py, jsuint8array.py: except: → except ImportError: around numpy optional import

All four files use the same pattern. The only exception that can occur is ImportError when numpy is absent. This prevents accidentally swallowing SystemExit or KeyboardInterrupt.