🚀 [Feature]: Support flow mappings `{a: 1, b: 2}`

[MariusStorhaug]

Companion to #7 (flow sequences). YAML 1.2.2 flow style for mappings — { key: value, key2: value2 } — is currently not parsed.

Request

ConvertFrom-Yaml should parse flow mappings inline anywhere a node is expected:

person: { name: Alice, age: 30 }
matrix: [{x: 1, y: 2}, {x: 3, y: 4}]

ConvertTo-Yaml does not need to emit flow style by default; block style remains the default output.

Spec examples covered

• Example 2.6 — Mapping of Mappings
• Parts of Example 2.27 (Invoice) once combined with other features

Out of scope

• Emitting flow style from ConvertTo-Yaml (would need a -Compress-style switch — separate decision)
• ? complex keys inside flow mappings (tracked separately)