Ship LongTable 0.2 beta: durable MCP Researcher Checkpoints and verified research packages

[HosungYou]

Why

Provider UI is transient; research commitments cannot live only inside it. LongTable 0.2 establishes a provider-neutral control plane in which human judgment, evidence provenance, and completion gates survive beyond one model, transport, or chat session.

Transient UI. Durable research decisions.

Product boundary

LongTable is a control-plane-first hybrid:

• Codex, Claude, and scholarly services execute replaceable discovery, reading, extraction, drafting, and rendering tasks.
• LongTable owns the Research Brief, Researcher Checkpoints, decision ledger, lawful-access records, claim-evidence links, visual contracts, and package verification.
• The public provider surface is reduced to $longtable and $longtable-research.

What changed

• Migrated the MCP server to the stable MCP 2026 input_required multi-round-trip flow.
• Removed the server-side 60-second push wait for modern clients; 2025 stdio clients remain supported through the SDK compatibility shim with a configurable 24-hour round watchdog.
• Persisted each checkpoint before presentation and made retries reuse the same QuestionRecord through durable response keys and caller idempotency keys.
• Added append-only transport attempts while keeping transportStatus as the compatibility projection.
• Kept decline, cancel, disconnect, and fallback from silently becoming research decisions; pending questions remain resumable across a fresh MCP process.
• Made accepted-answer replay return the existing linked DecisionRecord instead of duplicating it.
• Promoted the full test suite, including MCP stdio integration, into CI.
• Kept the lawful research runtime and Verified Research Package completion gates from the original beta.

Verification

• npm run release:check
• MCP 2026 stdio: accept, idempotent replay, decline, cancel, and fresh-process resume
• 65-second delayed form response: passed with one question and one linked decision
• full build, smoke suite, typecheck, and workspace package dry-run: passed
• npm audit --omit=dev --audit-level=high: 0 vulnerabilities

Claim boundary

The defensible claim is “No 60-second checkpoint loss: unanswered research decisions remain durable and resumable.” A host may still cancel its own UI, process, or network connection. LongTable guarantees durable recovery of the decision state; it does not claim control over every provider UI lifecycle.

Release boundary

The existing beta remains published under next as 0.2.0-beta.1; these new commits are verified on this PR branch but have not been republished or promoted to latest. This PR does not claim stable-channel promotion or completed researcher-productivity validation.