feat(pipelines): ✨ implement azdo pipelines folder create command

[tmeckel]

Implements the hardened spec of #263: create a build definition folder at PATH under PROJECT, mirroring az pipelines folder create.

Changes

• internal/cmd/util/scope.go: add ParseProjectPathTargetWithDefaultOrganization wrapper — parses [ORG:]PROJECT/PATH with an unbounded path (PATH may itself contain /), falling back to the configured default organization.
• internal/cmd/pipelines/folder/create/create.go: new azdo pipelines folder create [ORG:]PROJECT/PATH command with aliases c/cr, optional --description flag, JSON output passing the raw *build.Folder through, and plain output printing Created folder <path>.
• internal/cmd/pipelines/folder/folder.go: wire create into the folder command group.
• Tests: command tests (struct shape, missing-arg validation, success paths with/without description, nested paths, API error, JSON passthrough, default-org resolution) and parser wrapper tests.
• Docs: regenerated CLI documentation (docs/azdo_pipelines_folder_create.md).

Verification

• go test ./... — all 166 packages pass
• golangci-lint run --new-from-rev=HEAD — 0 issues
• make docs — docs regenerated

Closes #263