fix!: removed second auth header

[n3rdc4ptn]

Builds on: #4

This PR removes the MCPAuthorization header in favor of just using one auth header, the Authorization.

This follows best practices and reduces the risk of secret leakage, as the Authorization header is the pre defined http default header for tokens and authorization information and is respected in reverse proxies etc.

[Copilot]

Pull Request Overview

This PR removes the deprecated second auth header usage and related endpoints in favor of the standard "Authorization" header, reducing the risk of secret leakage. Key changes include:

• Removal of endpoints handling MCP authorization and the associated files (handlerWellKnownKubeconfig.go, handlerBtpSO.go).
• Updating of handler logic in mainHandler.go and _categoryHandler to exclusively use the "Authorization" header.
• Elimination of JSONPath handling in favor of solely supporting JQ in response processing.

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
internal/server/server.go	Removed routes for "/.well-known/openmcp/kubeconfig" and "/btp-so" endpoints
internal/server/handlerWellKnownKubeconfig.go	Removed the entire file as it relates to the deprecated auth header handling
internal/server/handlerMain.go	Updated auth header usage; removed fields and logic related to secondary and JSONPath support
internal/server/handlerCategory.go	Updated auth header usage and removed JSONPath-based logic in favor of JQ support
internal/server/handlerBtpSO.go	Removed the entire file to deprecate the old auth handling mechanism

Comments suppressed due to low confidence (3)

internal/server/server.go:15

• Since the routes '/.well-known/openmcp/kubeconfig' and '/btp-so' are removed, please update any corresponding API documentation or changelogs to reflect these endpoint removals.

mux.HandleFunc("/.well-known/openmcp/kubeconfig", defaultHandler(shared, wellKnownKubeconfigHandler))

internal/server/handlerMain.go:125

• The removal of the JSONPath branch in favor of solely using JQ may impact clients that rely on JSONPath processing. If JSONPath support is no longer required, please ensure this change is communicated and tested accordingly.

if (data.JQ == "") || k8sResp.StatusCode >= 400 {

internal/server/handlerCategory.go:110

• The JSONPath branch has been removed in _categoryHandler, which may affect clients expecting JSONPath support. Confirm that this change aligns with the overall API design and that clients have been notified of the adjustment.

if data.JQ != "" {