`common`: add partial regex support (#12808)

`common`: add partial regex support (#12808)

* move string_find_partial_stop & string_ends_with to common

* add common_regex (supports partial matches)

Co-authored-by: Georgi Gerganov <redacted>
* Update common/regex-partial.cpp

Co-authored-by: Georgi Gerganov <redacted>
* Update common/regex-partial.cpp

Co-authored-by: Georgi Gerganov <redacted>
* Update common/regex-partial.h

Co-authored-by: Georgi Gerganov <redacted>
* partial regex: add missing iterator end checks

* string utils: use string_views

* direct throw to avoid ggml.h include

* regex-partial: replace missed ggml_asserts

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Co-authored-by: ochafik <redacted>
Co-authored-by: Georgi Gerganov <redacted>