Add YAML emission presentation controls

[MariusStorhaug]

Context

YAML 1.2.2 offers multiple presentation styles for the same representation graph. The module currently emits a deterministic subset, while users need more control over scalar quoting, flow/block style, sequence indentation, and JSON-compatible output.

Official YAML 1.2.2 references:

• https://yaml.org/spec/1.2.2/#41-processes
• https://yaml.org/spec/1.2.2/#411-dump
• https://yaml.org/spec/1.2.2/#733-node-styles
• Normative module spec: spec/Emission-Presentation.md

Current State

Emission is deterministic and YAML-compatible, but presentation controls are limited. Strings and mapping keys are emitted double-quoted, collections use block style, and JSON-compatible emission is not exposed as a dedicated mode.

Objective

Expose idiomatic PowerShell controls for YAML presentation while keeping deterministic, safe output and preserving current defaults until a deliberate major-version change.

PowerShell Design Considerations

• Use validated parameters for style choices instead of switches that can combine into invalid states.
• Use parameter sets or validation to prevent conflicting presentation modes, especially JSON-compatible output versus YAML-specific style controls.
• Preserve pipeline behavior where multiple input records become a predictable document shape.
• Emit rich, classified errors when a requested presentation cannot represent the input graph.

Tasks

• Add scalar style controls for plain, double-quoted, and single-quoted output.
• Add collection style controls for block and flow output.
• Add indentation control for nested block sequences.
• Add JSON-compatible emission mode with clear incompatibility errors.
• Preserve deterministic output and idempotent re-emission for each option set.
• Document PowerShell examples for common pipeline and object scenarios.

Benefits

• Produces YAML that better matches user and tool expectations.
• Enables JSON-compatible output from the same value model.
• Keeps existing automation stable while allowing explicit presentation choices.

Acceptance Criteria

• Plain scalar emission quotes only when needed to preserve type and content.
• Double-quoted and single-quoted scalar modes behave predictably for keys and values.
• Flow-style output parses back to an equal representation graph.
• JSON mode emits valid JSON or rejects incompatible values with classified errors.
• Conflicting presentation options are rejected before output is written.

Related

• Spec folder: spec/Emission-Presentation.md