fix: document date alignment rules and add INVALID_ARGUMENT error for misaligned dates

[cnzj-Gc]

What type of PR is this?

• bug
• correction
• enhancement/feature
• cleanup
• documentation
• repository management
• tests

What this PR does / why we need it:

Closes #94.

The API description required startDate/endDate to align to day or hour boundaries depending on frequency, but nothing documented an error for misaligned values. The only OUT_OF_RANGE example covered endDate before startDate, which is a different condition.

Changes made:

• info.description now explicitly documents that misaligned startDate/endDate values result in 400 INVALID_ARGUMENT
• Added a GENERIC_400_INVALID_ARGUMENT_ALIGNMENT example to the Generic400 response
• Added test scenarios covering misaligned startDate/endDate for both DAY and HOUR frequencies

Which issue(s) this PR fixes:

Fixes #94

Special notes for reviewers:

Following the review comment on this issue, we used INVALID_ARGUMENT rather than OUT_OF_RANGE for the misalignment case. Per the CAMARA API Design Guide's Syntax Exceptions table, OUT_OF_RANGE is scoped to "a given field has a pre-defined range or an invalid filter criteria combination is requested". A date value that is not aligned to the frequency's day/hour boundary is a format error on a query parameter, which maps to INVALID_ARGUMENT ("Generic Syntax Exception", explicitly covering query params).

The existing _03_out_of_range_scenario is left unchanged, as it correctly covers a genuine OUT_OF_RANGE case (endDate before startDate).

Changelog input

Document date alignment rules and return INVALID_ARGUMENT for misaligned startDate/endDate in Network Traffic Analysis