fix(packets): keep the node filter pick on a slow click or late search (#2243) (#2244)

Fixes #2243.

## Problem

The packets node filter selected a suggestion on `click`, while the
input's `blur` handler hides the dropdown 200 ms after focus leaves. A
press held longer than that, or a search response that rebuilt the list
between mousedown and mouseup, lost the pick: the typed text stayed and
no `node=` filter was applied.

## Change

- `public/packets.js`: suggestions select on `mousedown` with
`preventDefault`, so the input keeps focus and the pick happens before
any rebuild. `live.js` already does this for its node filter.
- `public/packets.js`: a sequence counter drops search responses for an
older query, bumped on every search and on a pick, so a late response
can't replace or reopen the list.
- `tests/e2e/test-packets-node-filter-e2e.js` (new), registered in
`scripts/non-unit-tests.json` and on shard 1 in `deploy.yml`.

## Tests

The new E2E has three cases: a normal click, a 400 ms press, and a
search response released mid-click.

| Code | Normal click | 400 ms press | Response mid-click |
|---|---|---|---|
| master | pass | fail | fail |
| this PR without the sequence guard | pass | pass | fail (list reopens)
|
| this PR | pass | pass | pass |

Run locally against the freshened e2e fixture. `sh test-all.sh` passes
(locally `test-preflight-xss-gate.js` needs a real `python3` on PATH and
`PYTHONUTF8=1`, unrelated to this change).

## Not done

- Full `test-e2e-playwright.js` not run locally.
- Could not reproduce on the reporter's instance with the browser tool,
whose clicks are shorter than 200 ms. The 400 ms Playwright press
reproduces it on the fixture.
- `live.js` and `packets.js` still carry two separate node-autocomplete
implementations. Merging them is out of scope here.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

.github/workflows/deploy.yml

@@ -696,6 +696,7 @@ jobs:
           suite 2 test-marker-outline-weight.js CHROMIUM_REQUIRE=1 BASE_URL=$B
           suite 2 test-node-reach-e2e.js CHROMIUM_REQUIRE=1 BASE_URL=$B
           suite 3 test-packets-compact-columns-e2e.js CHROMIUM_REQUIRE=1 BASE_URL=$B
+          suite 1 test-packets-node-filter-e2e.js BASE_URL=$B
           suite 3 test-packets-scope-column.js CHROMIUM_REQUIRE=1 BASE_URL=$B
           suite 3 test-path-inspector-e2e.js CHROMIUM_REQUIRE=1 BASE_URL=$B
           suite 3 test-pr-1490-live-map-gpu-animations-e2e.js CHROMIUM_REQUIRE=1 BASE_URL=$B