Feature: add @oma-forge/shared for Forge API and OMA Core types

[ibrahimkzmv]

What

Adds @oma-forge/shared (packages/shared) as the single source of truth for Forge API types (RunSnapshot, ForgeEvent, ForgeTraceLine, DEFAULT_RUN_GOAL, parseForgeEvent) and re-exports of OMA Core types (TaskExecutionRecord, TeamRunResult, etc.). Server and web import from the shared package; duplicate types under apps/web/src/types/ and apps/server/src/runs/{types,trace-types}.ts are removed. Introduces ForgeDashboardRun for the DAG UI subset of TeamRunResult.

Why

Forge’s server <=> web contract was duplicated in two apps, which drifted from @open-multi-agent/core and made SSE/trace/run snapshots harder to keep in sync. A small shared workspace package keeps one typed contract and matches the v0.1 monorepo direction without pulling orchestration into the web bundle.

Checklist

• npm run lint passes
• npm test passes
• Added/updated tests for changed behavior
• No new runtime dependencies (or justified in the PR description)

Dependencies: Adds workspace package @oma-forge/shared, which depends on @open-multi-agent/core for type re-exports. Web consumes shared for types and parseForgeEvent only, OMA execution remains on the server. Root dev / build / lint build shared first.