docs/asset-engine: promote services.yaml to first-class contract

Adds the supporting infra around the service catalog now that it
has external consumers (the asset_engine UI being the first; CLIs,
monitoring, other services may follow):

- CATALOG-CONTRACT.md: the consumer-facing contract. Defines
  versioning policy (catalog_version vs per-service version),
  closed field-type and response-type vocabularies, recommended
  vendor+drift-check sync workflow, known-consumers list, service
  authoring notes.
- services.schema.json: JSON Schema (draft 2020-12) for the
  catalog. Generated from the Pydantic model in
  ~/development/asset_engine/src/asset_engine/catalog.py via
  `uv run scripts/dump_schema.py --publish`. Lets non-Python
  consumers validate against the same shape.
- services.yaml: adds catalog_version: 1 at the root and reframes
  the file's header to call out its first-class-contract status.
  Quotes a vibevoice label that contained an unescaped colon
  (caught by the asset_engine's strict YAML parser on first sync).

docs/asset-engine/services.yaml

@@ -1,15 +1,22 @@
-# services.yaml — inference services catalog on irv-ml1
+# services.yaml — canonical catalog of inference services on irv-ml1
 #
-# Drives the forthcoming asset-generation UI: each entry produces one
-# form (auto-generated from `fields:`) and one response renderer
-# (dispatched on `response.type`).
+# THIS IS A FIRST-CLASS CONTRACT. External consumers depend on the
+# shape and contents of this file. See CATALOG-CONTRACT.md alongside
+# for: schema reference, change-management policy, sync workflow for
+# downstream consumers, and known consumers list.
 #
-# Generated by an Explore-agent pass over stacks/<service>/{README.md,
-# compose.yaml,.env.example,server.py|infer-api.py}. Pydantic models
-# in code are the ground truth where they disagree with READMEs.
+# Drives form generators that auto-render UIs against the inference
+# services. Each entry produces one form (from `fields:`) and one
+# response renderer (dispatched on `response.type`). The field-type
+# vocabulary and response-type vocabulary are closed sets — see the
+# JSON Schema at services.schema.json or the contract doc.
 #
-# Schema is v1; bump per-service `version:` when fields change so old
-# Asset rows can still be interpreted.
+# `catalog_version`: bump when the SCHEMA changes (a field type added,
+# a required field removed, etc). Per-service `version:` bumps when a
+# specific service's parameter shape changes. Both let downstream
+# consumers detect drift.
+
+catalog_version: 1
 
 services:
   - id: kokoro
@@ -438,7 +445,7 @@ services:
         default: vibevoice
       - name: input
         type: textarea
-        label: Text (or Speaker N: ... script)
+        label: "Text (or Speaker N: ... script)"
         required: true
         description: >
           Single-speaker: plain text. Multi-speaker: "Speaker 0: ...\nSpeaker 1: ..."