Run Configuration: populate parameters & secrets from the build's declarations

[ChrisonSimtian]

Problem

The extension's Run Configuration view is free-form — it only shows params/secrets you hand-type. Declared members like NuGetApiKey ([Parameter][Secret]) don't appear, so the Secrets section looks empty.

Blocked on Fallout-build/Fallout#499 (the framework graph must emit parameters[] first).

Outcome

Run Configuration reads parameters[] from build-graph.json and pre-populates:

• non-secret params → Parameters rows (fill value → CLI args)
• [Secret] params → Secrets rows, shown "not set" until a value is entered (→ SecretStorage → env var on run)

Acceptance criteria

• NuGetApiKey and peers appear automatically after a build/plan.
• Declared secrets read "not set" until set; values live in SecretStorage, applied as env vars on run.
• Values still flow to runs as today (params → args, secrets → env); free-form add still works for extras.
• Graceful when the graph has no parameters[] (older builds) — falls back to today's free-form behaviour.