feat: add E2B sandbox provider

[vibhorgupta96]

Summary

Adds E2B as a secure, tenant-scoped sandbox provider that can be configured through the settings API.

Closes #387

Changes

• add a first-class E2B core provider for deterministic image-template builds, pause/auto-resume sandboxes, command execution, file transfer, and tenant ownership checks
• authenticate Code Mode WebSocket upgrades with the sandbox-bound E2B-Traffic-Access-Token while preserving the existing headerless Daytona and TFY paths
• add canonical discriminated E2B manifest/catalog schemas, provider dispatch, credential handling, persisted build metadata, runtime resolution, and status refresh
• move provider image builds outside database transactions, recheck all pre-build inputs under lock, retry concurrent changes, and return a declared 409 on exhaustion
• keep UI status wording provider-neutral and hide variants the current shared UI runtime cannot model without inventing Daytona lifecycle fields
• add focused core, API, schema, dispatch, persistence, and UI regression coverage plus release changesets

How was this tested?

• pnpm build
• pnpm test
• pnpm typecheck
• pnpm lint:ci
• pnpm format:check
• pnpm --filter @truefoundry/trueforge-core build

The restricted runner initially blocked the existing Unix-domain-socket probe with EPERM; the full root test suite passed when rerun with socket access.

Known limitation

• No live credentialed E2B integration run was possible; SDK boundaries are covered with injected/mocked tests.
• The current @truefoundry/assistant-ui-runtime config only models Daytona lifecycle fields. E2B is therefore API-configurable in this PR, but is intentionally not exposed as a UI catalog preset. UI creation can be enabled after the canonical runtime type is provider-neutral and CI regenerates the SDK/OpenAPI artifacts.

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

High Risk
Touches sandbox isolation, credential handling, and Code Mode WebSocket auth, plus concurrent settings persistence. A bug here can leak tenant sandboxes or hold provider credentials incorrectly.

Overview
Adds E2B as a first-class sandbox provider configurable through the settings API (not yet in the shared UI catalog).

The new E2BSandboxProvider builds a release image into an E2B template, creates secure, non-public sandboxes that pause/auto-resume, and proves ownership via trueforge_tenant_id metadata because E2B ids are opaque. Code Mode NATS now resolves a host plus optional WebSocket upgrade headers so E2B can send the sandbox-bound E2B-Traffic-Access-Token; Daytona/TFY stay headerless.

Settings manifests become a discriminated union (daytona | e2b). Image builds run outside the DB transaction, then persist only if preflight inputs still match under lock (retry, then 409). The UI keeps Daytona-only configure forms and uses provider-neutral “image build” wording.

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[changeset-bot]

🦋 Changeset detected

Latest commit: 7b45dd7

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

This PR includes changesets to release 4 packages

Name	Type
@truefoundry/trueforge-core	Minor
@truefoundry/trueforge	Minor
@truefoundry/trueforge-ui	Patch
frontend	Patch

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[debajyoti-truefoundry]

@vibhorgupta96 Please check #387 (comment)