fix: preserve numeric-looking inline strings

[developer0hye]

Summary

• Preserve inlineStr cell values as strings instead of guessing their type.
• Return string and rich-text cells unchanged from formatted_value() instead of applying numeric number-format coercion.
• Add parser-level regression coverage for a numeric-looking inline string (0050) through both raw and formatted value APIs.

Root cause

The XLSX reader routed inlineStr text through set_value_crate, which guesses scalar types. That converted values such as 0050 to the number 50, losing both the leading zeros and the source cell type. After preserving the raw string type, formatted_value() still passed the text through the number formatter, which again normalized it to 50 under the General format.

The reader now uses the existing set_value_string_crate path, and formatted text values bypass numeric formatting just as Excel text cells do.

Impact

Numeric-looking text stored as OOXML inline or shared strings now remains text through both value APIs. Numeric cells continue to use their number formats.

Validation

• cargo test (86 library tests, 112 integration tests, 4 streaming-writer tests, and 79 doc tests passed; 23 tests ignored)
• cargo clippy --lib -- -D warnings
• cargo +nightly fmt --all -- --check

[c-git]

I legit had this problem this morning. Thanks. I had some text with leading zeros and my zeros got removed.

[developer0hye]

@c-git cool

[MathNya]

@developer0hye
Thank you for the PR.
Since there were no issues, I’ll go ahead and merge it.