Carry the gesture no-effect fact on the snapshot tree like unsettledGesture #2856

Problem

A proven no-effect gesture (gestureNoEffect, #1600) reaches the agent only through capture annotations (withGestureNoEffectWarning in src/daemon/gesture-no-effect.ts). src/daemon/selector-capture-runtime.ts keeps only the SnapshotState and drops those annotations. So is, get, and find never show the no-effect warning; only snapshot does.

#2839 made SnapshotState.unsettledGesture the single carrier for the unsettled post-gesture fact. Every route derives its disclosure from that stamp: selector reads through withCaptureDisclosures, and snapshot through buildSnapshotWarnings.

Proposal

Move gestureNoEffect to the same stamp on the tree and derive its disclosure the same way. This deletes withGestureNoEffectWarning and the annotation channel for it, and gives selector reads the warning they miss today.

Follow-up to #2839.