[manifest] Emit .croco/manifest bundle

[kang-heewon]

Milestone

M1 - Contract Kernel

Priority

P1

Problem

Croco's generated artifacts should be visible as one inspectable bundle. Today, route contracts, diagnostics, provider readiness, runtime assumptions, DI graph, and policy metadata can be scattered across package-local checks.

Scope

Emit a .croco/manifest bundle for generated apps and contract checks.

Candidate files

.croco/manifest/contract-graph.json
.croco/manifest/problems.json
.croco/manifest/di-graph.json
.croco/manifest/runtime.json
.croco/manifest/policies.json
.croco/manifest/providers.json

Acceptance criteria

• Manifest files are deterministic and schema-versioned.
• A single drift check can compare committed/generated manifests where applicable.
• Manifest entries include source locations where possible.
• croco doctor can read the manifest bundle.
• Generated docs/OpenAPI/RPC clients can reference the same manifest source.