Add test for exact googol (10**100) in intword

[BlocksecPHD]

Summary

This PR adds a test case for exact googol (10**100) in intword() function.

Context

• Issue intword fails to parse numbers >= 1 Googol #134 reported that intword(10**100) returns the raw number instead of "1.0 googol"
• PR Fix plural form for intword and improve performance #273 fixed the underlying issue by using bisect instead of for-loop
• However, the test for exact googol was not added in that PR
• The existing tests cover 2e100 (2 googols) and 10**101 (10 googols), but not 10**100 (1 googol)

Changes

Added test case ([10**100], "1.0 googol") to tests/test_number.py

Testing

This test will pass once version 4.15.0 (containing the fix from PR #273) is released to PyPI. The test ensures the googol edge case is properly covered for future releases.

Fixes #134