Accept any Runtime image name in the Runtime reference

[SaladDay]

Rename step W1 (design 60-rename-oac-design.md): the Web stops hard-coding the Runtime image name in the Runtime reference.

The Runtime reference prefix changes from parsar-core-runtime@sha256:… to oac-runtime@sha256:… in the backend's R2. Before this change, two Web regexes required the old prefix, so R2's manifest would have broken the setup wizard.

Change

One shared RUNTIME_REF_PATTERN = /^[a-z0-9][a-z0-9._-]*@sha256:[0-9a-f]{64}$/ now serves both:

• the manifest parser (deployment-specification.ts);
• the wizard's microsandbox_ref field check (runtime-release.ts).

Core stays the authority: it checks the reference against the manifest exactly. The Web only checks the shape before submitting.

Tests

• A new unit test accepts parsar-core-runtime@… and oac-runtime@…, and rejects a ref without @sha256:, a short digest, uppercase hex and an empty name.
• Results: typecheck ✓, web tests 367, nodes.spec.ts 8/8.

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