feat(integration): close Ariadne tasks hydration spec v1 gaps

[imjmedia]

Summary

• Completes the remaining gaps from the Ariadne NEW→LEG tasks hydration spec (v1) on top of feat(integration): hydrate tasksJson from Ariadne change packs #538.
• Adds dedicated markdown parser, change_plan_seed mapping, idempotent re-import (idempotencyKey / generatedAt / forceTasksRefresh), and skipBaselineDeliverables enforcement in legacy cascade.
• Adds warn-only Gate 2 validate-tasks-json call, IntegrationPanel handoff kind badges + markdown preview, and Ver tareas navigation.

Changes

Area	Detail
shared-types	parseAriadneCursorTasksMarkdown, mapChangePlanSeedToTasksJsonPayload, mergeTasksJsonIdempotent, resolveSkipBaselineDeliverableKinds, stricter validateTasksJsonV2 (source + projectId)
API	Idempotent import in applyIntegrationHandoffTasks, persist skipBaselineDeliverables, orchestrator skip kinds, recommendedNextTools aligned with spec
Web	IntegrationPanel seed items + Ver tareas; Tasks panel hint when hydrated; cascade UI respects skip kinds
Docs	docs/contracts/theforge-tasks-hydration-from-ariadne-v1.md updated

Test plan

• Import integration pack with tasks_json_seed → Tasks panel shows T-001+ with file paths
• Re-import same idempotencyKey → no duplicate tasks; merge by task id when newer generatedAt
• forceTasksRefresh: true → replaces tasksJson wholesale
• Fallback: only cursor_tasks_markdown → parser populates tasksJson
• skipBaselineDeliverables: ["migration_tasks","change_spec"] → no legacy_generate_deliverables in recommended tools; cascade skips those kinds
• LEGACY IntegrationPanel: badges on seed kinds, markdown preview, Ver tareas opens Tasks tab
• get_tasks_json / get_next_implementation_task unchanged behavior with hydrated SSOT