build: generate the TechLog Studio contract from canonical source

Vendors the canonical studio-v1.yaml, generates types via an isolated
`pnpm dlx` toolchain (openapi-typescript needs TypeScript 5's classic
compiler API; this repo pins TypeScript 7.0.2 per VD-01, whose root
export has none), and adds an offline drift gate that checks the
vendored yaml/generated types/canonical-source.json against each
other without touching the sibling design-package repo or the network.

Regenerating from canonical surfaces real, new required fields on
existing schemas (WorkingCopyDetail.nextAction, PreviewDetail/PublicPreview
.dependencyRevision, StudioDashboard.totals.needsValidation,
PublicationSnapshot.contentFormatVersion/rendererContractVersion) and a
new required EvidenceFigureBlock.asset. The mock gateway and fixtures
are updated to satisfy the former; the latter exposes a real authoring-
vs-rendering conflation in the content-format parser (it declared its
output as the server's fully-resolved PublicRenderModel type, which it
has no asset catalog to satisfy). Split that boundary: the parser now
produces an authoring block type omitting the resolved asset, and each
of its three consumers (the mock gateway, the Studio instant preview,
and the static Case demo page) attaches the resolved descriptor from
its own asset source through a shared, pure domain-level resolver.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/features/tech-log/contracts/studio/canonical-source.json

@@ -0,0 +1,27 @@
+{
+  "packageId": "tech-log-studio-contract",
+  "version": "2.0.0",
+  "digest": "sha256:99f54f56ea0c582eafdbdf9be5653e3384bef0a1b08bff67f3147ee0292019ea",
+  "sourceRevision": "ce2e748",
+  "operationIds": [
+    "getStudioSession",
+    "getStudioDashboard",
+    "listStudioDocuments",
+    "createStudioDocument",
+    "getStudioDocument",
+    "saveStudioDocument",
+    "validateStudioDocument",
+    "getCurrentStudioPreview",
+    "createStudioPreview",
+    "publishStudioDocument",
+    "listStudioPublications",
+    "unpublishStudioPublication",
+    "getStudioPublicationSnapshot",
+    "listStudioCatalog",
+    "listStudioAssets",
+    "uploadStudioAsset",
+    "getStudioAsset",
+    "updateStudioAsset",
+    "deleteStudioAsset"
+  ]
+}