feat: wrap dashboard stores in responsive grid

[dltacube]

What changed

Reworks the dashboard matrix from a single fixed table into responsive per-series cards with a store grid. Store cells now wrap within the viewport instead of compressing into one row or disappearing off the right edge when many stores are selected.

Why

With a large STORES selection, the current table layout puts every store in one table row. In the screenshot harness, the rendered table was 4019 px wide inside a 998 px matrix area, making the dashboard hard to scan.

The new layout keeps each series in a bounded panel and lets store cells wrap within the available width.

Scope

Visual-only web dashboard change. The PR touches only web/index.html and does not change store polling, notification behavior, checkout behavior, or the matrix API contract.

Validation

• git diff --check
• Captured before/after screenshots with a mocked 50-store /api/matrix response.

Screenshot artifacts captured locally:

• Before: /tmp/streetmerchant-webui-pr-screenshots/before-dashboard.png
• After: /tmp/streetmerchant-webui-pr-screenshots/after-dashboard.png
• Metrics: /tmp/streetmerchant-webui-pr-screenshots/layout-metrics.json

Measured at a 1024x768 viewport:

before table width: 4019 px inside a 998 px matrix area
after grid width:    972 px inside a 998 px matrix area
after wrapped:       50 store tiles across 8 rows

Screenshots are intentionally kept out of the commit so the PR remains a visual-only source change.

[Mr-Tech-13]

I like this change, when I was testing my web ui PR I never tested more than a handful of stores. I was more concerned about the functionality of changing stores while the program is running.

[jef]

thanks for the input @Mr-Tech-13 !

[dltacube]

@jef not sure what to do about the lint pull request title workflow. Can that be overlooked?

[dltacube]

@jef the title is conventional now. Could you approve/rerun the Pull Request Linter? The latest run is stuck as action_required.