[3/3] core: replay persisted world state

[sayan-oai]

Why

Persisting WorldState snapshots and patches is only useful if resume and fork restore that exact comparison baseline. Rebuilding it from TurnContextItem loses section state and can either repeat or suppress model-visible updates.

This is the third PR in the WorldState persistence stack, built on #29835.

What

• Replay full WorldState snapshots and RFC 7386 patches through the existing rollout reconstruction segments.
• Discard state from rolled-back turns and treat compaction as a baseline reset.
• Hydrate ContextManager from the reconstructed snapshot on resume and fork.
• Remove the synthetic TurnContextItem to WorldState conversion path.
• Leave legacy or malformed rollouts without a baseline so the next update safely emits a full snapshot.

Testing

• just test -p codex-core world_state
• just test -p codex-core rollout_reconstruction_tests
• just fix -p codex-core
• just test -p codex-core (the changed tests passed; the full run also hit unrelated existing/test-environment failures, primarily a missing test_stdio_server binary)

[chatgpt-codex-connector]

💡 Codex Review

codex/codex-rs/core/src/session/mod.rs

Lines 1408 to 1409 in 8b3962c

	if let Some(world_state) = world_state_baseline {
	state.history.set_world_state_baseline(world_state);

Add integration coverage for world-state resume replay

This resume/fork hydration path changes the agent's first model request after reconstructing a rollout, but the commit only adds session/rollout_reconstruction_tests.rs unit-level coverage; I don't see a core/tests/suite TestCodex resume/fork test that verifies the actual resumed request doesn't duplicate or suppress environment context. The repo guidance requires integration tests for agent-logic changes, so please add one around replaying persisted world state on resume or fork.

AGENTS.md reference: AGENTS.md:L115-L119

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