feat: surface failed-run and missed-deadline indicators in the Grid view and add Deadlines tab to DAG run detail

[imrichardwu]

This PR adds two complementary pieces of UI feedback for DAG runs in the Grid view:

1. Failed-run indicator – a warning icon (triangle with "!") is rendered above the
   duration bar for any run whose state is failed. Clicking the icon navigates directly
   to the run detail page (task-instances view), letting operators drill in without first
   having to select the bar.

2. Missed-deadline indicator – a clock/deadline icon is rendered above the duration bar
   (stacked above the failed icon when both apply) for any run that has at least one missed
   deadline. Clicking it navigates to the new Deadlines tab described below.

Backend changes

• GridRunsResponse (datamodel) gains a has_missed_deadline: bool field so the grid
  endpoint can communicate per-run deadline status without an extra round-trip.
• A new private-UI router deadlines_router is mounted at /ui/deadlines/{dag_id}/{run_id}.
  The endpoint fetches all Deadline rows for the given DAG run (joined with the associated
  DeadlineAlert for name/description), orders them by deadline_time, and returns a list
  of DeadlineResponse objects.
• DeadlineResponse exposes: id, deadline_time, missed, created_at,
  alert_name (nullable), alert_description (nullable).
• The OpenAPI private-UI spec (_private_ui.yaml) is updated accordingly, and the generated
  TypeScript client is regenerated.

Frontend changes

• FailedIcon – new Chakra createIcon SVG component (warning triangle) for React usage.
• DeadlineIcon – new Chakra createIcon SVG component (clock) for React usage.
• failedIconPlugin – Chart.js plugin that draws warning triangles on the canvas above
  failed bars inside DurationChart. (The canvas plugin path is kept separate from the
  React icon because Chart.js operates on a <canvas> element.)
• Bar (Grid/Bar.tsx) – renders the FailedIcon and/or DeadlineIcon as absolute-
  positioned ghost buttons above each bar, with dynamic vertical offsets so the icons
  never overlap the bar or each other.
• Deadlines page (pages/Run/Deadlines.tsx) – sortable, filterable table of deadlines
  for a DAG run. Columns: alert name, deadline time, status (Missed / On Track badge),
  created at, description. A checkbox filters to missed deadlines only.
• Router and Run detail view are updated to include the new deadlines tab route.

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[vincbeck]

Suggestion: can you split your PR into 2? One for the back-end, one for the front-end? It would make it easier to review, plus, very often back-end and front-end are not reviewed by the same persons so that way you get "specialized" reviews on back-end and front-end :)

[imrichardwu]

Suggestion: can you split your PR into 2? One for the back-end, one for the front-end? It would make it easier to review, plus, very often back-end and front-end are not reviewed by the same persons so that way you get "specialized" reviews on back-end and front-end :)

here is the pr for the backend: #62189
here is the pr for the frontend: #62195