refactor(labs): narrow causal document ports

[developer-1px]

Summary

• narrow id resolution to the query/at read port
• narrow stable-id materialization to current projection reads and patch preflight
• let direct/positional causal inboxes use only publication methods while stable-id configs opt into the extended port
• preserve full JSONDocument and Parameters<> compatibility and document synchronous publication/reference invariants

Why

Canvas needs to validate and synchronize its canonical DesignDocument projection without exposing the complete internal JSONDocument command/history surface. This keeps the core public API unchanged while giving the private causal lab a deep adapter seam for the next dogfood tracer.

Verification

• id-resolver: 7 tests, typecheck, build
• stable-id-rebase: 19 tests, typecheck, build
• causal-patch-inbox: 58 tests, typecheck, build
• all 41 extension labs verified
• docs generation/evaluation
• independent interface review: no blockers
• git diff --check