Update session metrics on createTurn and terminal writes

[bhaveshpatel640]

Summary

Update session.metrics in the same transactions as turn writes: turn count on create, cost and duration on a winning terminal transition.

Linear: AGE-2010

Changes

• createTurn increments total_turns on the session tip update (same tx)
• running → terminal (updateTurnState, or freeze when cancel applies) adds total_cost_in_usd and completed_at − created_at
• Postgres, SQLite, and InMemory; store contract tests for increment, cost/duration, two-turn sums, freeze once.

How was this tested?

• Store contract (InMemory) plus pnpm test:store:sqlite and scripts/test-store-local.sh

Checklist

• I have read the contributing guidelines
• pnpm build, pnpm test, pnpm typecheck, pnpm lint:ci, and pnpm format:check pass locally
• Tests added/updated where it makes sense
• No hand-edits to generated code (packages/trueforge-sdk, .github/fern/openapi/openapi.json, docs/openapi.json) — fork PRs omit SDK regen; maintainers regenerate after merge
• Docs / .env.example updated if configuration or behavior changed

---

Note

Medium Risk
Changes core session-store write paths and how usage/cost totals are derived; incorrect folding or double-counting would affect session-level metrics, though behavior is transactional and covered by contract tests.

Overview
Session metrics are now updated in the same atomic operations as turn lifecycle writes, so turn count, cost, and duration stay consistent with persisted turns without separate aggregation.

createTurn increments session.metrics.total_turns on the existing session tip update (Postgres/SQLite via jsonb_set, InMemory in process). Cost and duration are not touched at create time.

Winning terminal transitions (updateTurnState when running → done/cancelled/error, and freezeAndGetTurn only when the cancel UPDATE actually matches) fold total_cost_in_usd from terminal turn metrics and total_duration_ms as completed_at − turn.created_at (truncated, floored at 0). Already-terminal freezes and losing second terminal writes do not double-count. Postgres sums duration with bigint to avoid int overflow on long sessions.

The ISessionStore contract documents this behavior; shared store contract tests cover increment-only on create, single fold on terminal/freeze, conflict paths, and multi-turn accumulation.

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🦋 Changeset detected

Latest commit: de3ba3e

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@truefoundry/trueforge-core	Patch
@truefoundry/trueforge	Patch

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