[SaladDay]

Providers currently depend on Runtime's private credential storage, while node deployment rules and Harness interactions have parallel definitions. This change gives these boundaries one current contract and removes retired project wire paths.

• Docker, microsandbox and E2B deliver a validated Runtime bootstrap input; Runtime consumes it without modifying saved enrollment credentials.
• Harnesses share the interaction response format and a reusable lifecycle conformance suite. Retired tool snapshots and node wire fallbacks are removed.
• Go owns deployment-spec rules and generates the Python projection, with shared canonical JSON/digest fixtures.
• Canonical guides, architecture references and generated documentation describe the current ownership boundaries.

Core and Runtime must be built from this revision together (Runtime wire 0.9.0, node wire 3). This does not add historical upgrades or change the pinned public API.

Validation:

• Completed all make check gates, resuming failed setup/build stages after correction. Web browser acceptance used cached Chromium through an external host-only configuration because Chrome is unavailable: 83/86 passed initially and the three failed tests passed on a targeted rerun. Example browser acceptance: 10/10.
• Focused Runtime/Harness/Provider tests, deployment fixtures, 175 E2B helper tests, generated-doc checks and standalone Core packaging passed.
• After integrating main, reran documentation generation/build, the Runtime contract suite, all Harness Go tests and both confirmed/uncertain preparation-failure regressions.
• A fresh independent review found no actionable issues in the complete implementation diff. Main integrated cleanly except the generated guide index, which was regenerated from merged sources.

Live-model limitation: the optional Claude/MiniMax acceptance scenario did not pass exact response-marker assertions in function resume/steering. Recorded function delivery and steering receipts succeeded; this is not a claim of full live acceptance.

Integrated main through #239 and #240 (906bc67), preserving the distinction between confirmed preparation failure and retryable uncertain states.