frameobject.c: FrameLocalsProxy swallows and overwrites real errors

Summary

Two bugs:

1. framelocalsproxy_inplace_or (line 573) returns Py_NotImplemented instead of NULL when merge fails → exceptions silently discarded.
2. framelocalsproxy_update (line 730) unconditionally replaces any exception with TypeError.

Reproducer

import sys
frame = sys._getframe()
locs = frame.f_locals

class BadDict(dict):
    def keys(self):
        raise RuntimeError("keys() failed!")

# Bug 1: |= swallows the error
try:
    locs |= BadDict()
    print("|= silently swallowed RuntimeError (BUG)")
except RuntimeError:
    print("|= correctly propagated")

# Bug 2: .update() replaces RuntimeError with TypeError
try:
    locs.update(BadDict())
except TypeError:
    print("update() masked RuntimeError as TypeError (BUG)")
except RuntimeError:
    print("update() correctly propagated")