Stop mirroring goes through the confirm page, which names the mirror and says nothing more is pushed #7979

Intent: stopping an outbound mirror asks first like every other settings removal; today src/web/pages/settings.ts draws "Stop mirroring" as a plain POST form to <base>/settings/mirror/stop.

Done looks like:

• [ ] The button is confirmAction({ action: ${base}/settings/mirror/stop, verb: "Stop mirroring" }); the mirror line and the "Stopping leaves … as it is" sentence stay.
• [ ] DESTRUCTIVE in src/web/pages/search.ts gets one entry for ^/([^/]+)/([^/]+)/settings/mirror/stop$, added directly after the settings/proposal-tokens entry: verb "Stop mirroring", title "Stop mirroring <owner>/<name>?", detail "The copy on the other side stays as it is; nothing more is pushed to it. This cannot be turned back on from the settings page.", phrase "".
• [ ] mirrorStop is unchanged.
• [ ] A new test/confirm-mirror-stop.test.ts proves the settings page links the button to /-/confirm?to=…/settings/mirror/stop and the confirm page answers 200 with that title for an admin; it fails without the change.
• [ ] bun test test/confirm-mirror-stop.test.ts test/mirror-target.test.ts passes; bun scripts/design-lint.ts is clean.

Files: src/web/pages/settings.ts, src/web/pages/search.ts, test/confirm-mirror-stop.test.ts Risks: search.ts and settings.ts are touched by sibling issues at other places; keep the edit to the one form and the one entry. Brief: a builder who knows the web pages.