Generate OpenAPI contracts for native REST mutations

[DandyLyons]

Generated OpenAPI omitted the native server's enabled mutation routes. It now describes CRUD, identity edits, UUID repair, named/path aliases, operation status, and recovery from the same immutable endpoint plan used by Hummingbird.

Request schemas follow each resource's writable codec, creation identifiers, and identity-edit fields. Shared components describe canonical revision tokens, durable receipts, validation diagnostics/fix-its, conformance changes, and committed-but-unpublished recovery outcomes. DELETE is documented with its implemented 200 receipt response. Read contracts retain pagination/search behavior and now document freshness, generation, and revision headers.

Refs #108; follows completed #155 and precedes #152 → #142 in #93. No mutation behavior changes.

Validation:

• Full macOS Swift suite: 1,520 tests passed; subsequent final contract suite: 9 tests passed, including the added metadata-only codec case.
• Build, CLI help, deterministic JSON/YAML, strict OpenAPI 3.1 validation, served/offline byte parity, and exact route-registration parity passed.
• Actual Hummingbird receipt/error bodies validate against generated schemas across all mutation actions and all five receipt states.
• Linux: server build/smoke, 129 focused server/template tests, and CLI/server release builds passed. The final committed OpenAPI source/tests also passed all 9 contract tests in the Linux image.