release: fold #637 into the 1.9.0 changelog section (#648)

Same bookkeeping as #645 for the last rolled-in PR (#647): the entry
moves from Unreleased into the section v1.9.0 actually ships.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

Author: VijitSingh97

CHANGELOG.md

@@ -11,16 +11,6 @@ per the process in [`docs/releasing.md`](docs/releasing.md).
 
 ## [Unreleased]
 
-### Added
-
-- **One-click upgrade names its restore point (#637).** Before an in-place upgrade overwrites
-  the running install, the runner copies `config.json` and the rendered `.env` to timestamped
-  `.bak-upgrade-*` siblings — and refuses to proceed if it cannot; a failure during the
-  upgrade names those copies in the result and the dashboard modal. On the versioned layout
-  the result (and the "Upgraded" modal) names the previous version dir — the rollback copy
-  #629 already kept but never pointed at. The copies are written symlink-safely (mktemp +
-  rename, the #629 co-tenant threat model) and pruned to the newest three pairs.
-
 ## [1.9.0] - 2026-07-18
 
 **Stratum link security.** v1.9 locks the last cleartext link — miner ↔ stack
@@ -33,6 +23,14 @@ steady-state CPU cost drops via healthcheck and peer-count tuning (#595).
 
 ### Added
 
+- **One-click upgrade names its restore point (#637).** Before an in-place upgrade overwrites
+  the running install, the runner copies `config.json` and the rendered `.env` to timestamped
+  `.bak-upgrade-*` siblings — and refuses to proceed if it cannot; a failure during the
+  upgrade names those copies in the result and the dashboard modal. On the versioned layout
+  the result (and the "Upgraded" modal) names the previous version dir — the rollback copy
+  #629 already kept but never pointed at. The copies are written symlink-safely (mktemp +
+  rename, the #629 co-tenant threat model) and pruned to the newest three pairs.
+
 - **XvB raffle wins on the chart and in a log (#644).** The dashboard reads XvB's public winners
   log (over Tor, about every 30 minutes) and records every round your wallet won. Wins show as
   gold stars on the hashrate chart (hover for the round type and credited hashrate), as a