[mortenzwarenstein]

Description

WMS vendor specific parameters for the benefit of ogcapi-maps

Type of change

• Improvement of existing feature

Checklist:

• I've double-checked the code in this PR myself
• I've left the code better than before (boy scout rule)
• The code is readable, comments are added that explain hard or non-obvious parts.
• I've expanded/improved the (unit) tests, when applicable
• I've run (unit) tests that prove my solution works
• There's no sensitive information like credentials in my PR

[Copilot]

🟡 Changes recommended

GetMap tests lack coverage for vendor-parameter round trips and mixed-case standard-key collisions, allowing regressions in parameter preservation and collision protection to pass unnoticed.

1 open issue

• Add GetMap tests for vendor parameters and collision handling · New

What changed in this PR

Adds vendor-specific parameter support to WMS 1.3.0 GetMap requests for use by OGC API Maps.

Changes:

• Preserves vendor parameters during query parsing and serialization.
• Prevents vendor parameters from overriding standard WMS keys, regardless of case.
• Introduces a shared CRS query-key constant and uses it in GetFeatureInfo.

File	Description
pkg/​wms130/​getmap_request.go	Adds the vendor-parameter field and populates it during parsing.
pkg/​wms130/​getmap_request_pv.go	Parses and serializes vendor parameters while filtering standard-key collisions.
pkg/​wms130/​getfeatureinfo_request_pv.go	Replaces CRS string literals with the shared constant.
pkg/​wms130/​common.go	Defines the shared CRS_KEY constant.

_{Review effort: Balanced}