fix(click): observe post-click effects + scope snapshot locators to modal

[kepptic]

Summary

• ghax click now reports observable downstream effects — dialogDismissed, urlChanged, preDialogCount, postDialogCount, observedMs — alongside the existing ok. Default 300ms budget, configurable via --observe-ms <n>, opt-out via --no-observe. Fixes the silent-no-op confusion where loc.click() resolved before React actually unmounted a confirm modal.
• ghax snapshot now scopes per-node Locators to the auto-detected modal when dialog-scope kicks in. Previously the rendered ARIA tree was modal-only but getByRole(...) ran page-wide, so a same-named button outside the modal could trigger strict-mode errors or, where Playwright's pick resolved uniquely, silently click the wrong element. Stacked dialogs (HubSpot stacks an alertdialog over an already-open dialog) hit this routinely.
• Smoke flake fix — console --dedup test now uses a per-run marker so the daemon's CircularBuffer can no longer cause count=10 on a second smoke run against the same daemon.

Why this matters

A field report described ghax click @e<ref> returning {ok: true} on the HubSpot "Yes, save" confirmation modal but the modal not dismissing. Reproduced live: the click was dispatched correctly via Playwright's CDP Input.dispatchMouseEvent (so isTrusted: true — that hypothesis was wrong); HubSpot just runs an async network round-trip before unmounting the dialog, ~1.3s later. The old {ok: true} told callers nothing about whether the effect landed. Agents retry, double-save.

The new fields let agents write deterministic checks like if (!result.dialogDismissed && !result.urlChanged) retry().

Test plan

• npm run typecheck
• npm run build
• cargo build --release
• GHAX_BIN=$PWD/target/release/ghax npm run test:smoke — 99/99 pass in ~400s
• Live HubSpot repro on /service-keys/21999358/key/38111555:
  • click Edit → urlChanged: true, postDialogCount: 1
  • click Save → preDialogCount: 1, postDialogCount: 2 (alertdialog stacks)
  • click "Yes, save" --observe-ms 2500 → urlChanged: true

New smoke checks

• click reports dialogDismissed when a modal closes
• click reports dialogDismissed=false when nothing changes
• click --no-observe skips post-click observation
• snapshot scopes locators to the auto-detected modal