* fix: accept HK autocomplete codes on home analysis input
The home page stock input accepted plain A-share codes but rejected Hong Kong stocks selected from autocomplete. The root cause was that autocomplete submits the suggestion canonicalCode (for example 00700.HK), while the backend stock code utility only recognized .SH/.SZ/.SS suffixes. As a result, 00700.HK was treated as mixed alphanumeric noise and rejected with the generic validation error before analysis dispatch.
Extend shared stock code recognition and normalization to accept .HK suffixes alongside existing A-share suffixes. This keeps the existing manual input behavior for 00700 and makes the backend consistent with the canonicalCode format already used by the web stock index and autocomplete flow.
Add regression coverage on both sides of the boundary: backend contract tests now verify that trigger_analysis accepts 00700.HK from autocomplete and HK00700 from manual input, and frontend tests now verify that highlighted HK suggestions submit the canonical .HK code and are not rejected by local store validation.
* update CHANGELOG.md
* fix: align HK code validation with existing market rules
Follow up the home page HK autocomplete fix by tightening the shared stock code validator so exchange suffixes and prefixes no longer reuse the same generic 5-6 digit rule.
This change keeps SH/SZ/SS suffixes restricted to 6-digit mainland codes, treats HK suffixes and HK prefixes as 1-5 digit Hong Kong codes with zero-padding during normalization, and rejects invalid cross-market combinations such as 600519.HK, HK600519, and 00700.SH.
Add regression coverage for valid short HK forms like 1810.HK and HK700, plus negative tests for invalid suffix and prefix lengths, so the shared backend utility stays consistent with the existing web validation and data-provider normalization rules.
