Standardize the runtime graph

[anth-volk]

Implements the OpenSpec change standardize-runtime-graph as an independently owned child of #873.

Status: blocked

This pull request is blocked on both PR #873 and discussion with @MaxGhenis to confirm the intended runtime-graph direction. It should not be merged until #873 is ready and that design direction has been agreed.

Recorded #873 base: ee617ea672a7a81b4a86b3c03091a29f084682d4

This branch pushes only to origin/codex/standardize-runtime-graph. It does not modify Max Ghenis's model-artifact-graph-20260904 branch.

Implemented commit series

1. e713860d documents the typed-artifact baseline inherited from Add reusable typed model artifacts and transfer graphs #873, the Root identity: hash-pin every raw microdata input and reference its Chronicle registration (#848) #853 source-identity boundary, and the child-branch update procedure.
2. 5f09e9a9 adds restricted, versioned Graph YAML; safe deterministic module composition; declared parameter binding; exact lowering; and optional generated Graph JSON.
3. 08abe4a0 adds recursively immutable parameters, unchanged-row value revision, multi-population union, named products, and explicit earlier-weight-state references.
4. 6707637a adds source identity verification, declaration-controlled decoding, source/codec identity propagation, stored validation outcomes, required-success dependencies, and graph-bound schema-v4 run manifests.
5. 54a0bdb3 adds saved-run population reconstruction, versioned local materializers, candidate indexes, the one-plan shared runner, and storage deduplication evidence.
6. d08ebceb adds UK/US YAML and generated-JSON equivalence tests, package and wheel checks, interface documentation/locking, focused acceptance scenarios, and the changelog entry.

Result

• YAML is the authoritative human-authored Graph source.
• One compiled microcosm.graph.Graph is executed once per shared-runner invocation.
• Optional generated Graph JSON is a derived, lossless serialization.
• Kernels remain registered black-box functions with read-only declared inputs and validated declared effects.
• Values, structural frames, weights, lineage, validation outcomes, and typed artifacts are content-addressed; run manifests reference them.
• Named population products can be reconstructed from the Graph, saved manifest, and content store without sources, kernels, or kernel execution.
• Local compatibility artifacts are materialized after the run manifest is saved. External publication is not part of graph execution or materialization.

Verification

• openspec validate standardize-runtime-graph --strict
• uv run --package microcosm-graph ruff check .
• uv run --package microcosm-graph pytest packages/microcosm-graph/tests -q
• shared build YAML/parser/schema/re-emission tests
• UK and US semantic parity/equivalence tests
• uv run tools/ci_test_groups.py --verify
• uv lock --check
• clean wheel build/install/import and packaged-schema check

OpenSpec progress is 36/38. The two unchecked tasks are conditional lifecycle work: rebase and revalidate if #873 changes, then rebase onto main and retarget this pull request after #873 merges. #873 remains open at the recorded commit, so neither condition currently applies.

[anth-volk]

Superseded by #893