fix(index): settle graph-off retained text wakes

[BleedingDev]

Summary

• bypass full retained-generation seating when native graph activation is disabled
• let graph-off worktrees reconcile through the retained text owner
• drain a stale no-work notification without suppressing real arrivals or raw overflow

Why

A graph-off worktree could enter an empty full-serving slot, then consume a stale coalesced wake as a second fake refresh. The exact unchanged-source journey consequently reported refreshing instead of fresh.

Verification

• exact stale-witness regression passes 6 consecutive runs
• all four graph-off scheduler tests pass
• aggregate focused suite: 14 passed
• Rustfmt and diff checks pass

Supports #707.

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[chatgpt-codex-connector]

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Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-08-30T15:33:58.472946Z	79dba08	PR opened

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[chatgpt-codex-connector]

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Reviewed commit: 79dba08e75

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[chatgpt-codex-connector]

Preserve legitimate graph-off remount wakes

When an already-ready graph-off mount is remounted while an unhinted filesystem edit races the remount, this continue drops the only reconciliation wake. replace_existing_semantic_schedule deliberately emits a bare scheduler.wake.notify_one() so the next pass detects such an edit, but it sets neither PendingWakeV1 nor a scheduler hint; consequently this predicate misclassifies that wake as a stale text-slice permit and exact/lexical queries keep serving the retained generation until an unrelated later wake. Track the text-slice follow-up explicitly, or make meaningful control wakes establish pending work.

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