feat(workflow): support adaptive revisions

[trvon]

Summary

• add durable, typed WorkflowRevise operations for adding/revising future states and adding/redirecting transitions
• enforce revision/state/transition-sequence CAS, definition-revision transition fencing, lease authorization, graph constraints, bounded definitions, and immutable revision history
• keep workflow definitions, executions, revisions, history, and leases exclusively in LoopStore; standalone TaskStore remains independent
• consolidate maintained documentation into README, AGENTS, usage, reference, testing, changelog, and a minimal GitHub security pointer

Safety and recovery

• current materialized work and its lease remain immutable during revision
• newly entered task phases remain unowned until explicit WorkflowClaim
• rejected revisions are byte-preserving, including legacy snapshots normalized in memory
• persisted revision history is schema-validated and fails closed on corruption
• accepted revision logic executes once through the authoritative reducer
• server-resolved runtime identity is not exposed in the public revision request contract

Commits

• c444749 feat(workflow): support adaptive revisions
• 790b67d docs: consolidate project guidance