Add Dag ID filtering to Assets search

[shivaam]

Large Asset catalogs need a direct way to find the Assets related to a specific Dag. This adds an exact-match Dag ID filter to Search Assets using the existing UI Assets API support.

The filter:

• appears in the existing Assets Filter menu;
• sends the selected value through the generated dagIds query parameter;
• keeps the selection in the URL so filtered views are shareable and survive reloads;
• synchronizes the active filter pill with browser Back/Forward navigation; and
• omits empty values while preserving the existing pagination-reset behavior.

This is a focused part of the broader Assets-filter work in related: #53052; it does not close the issue or add the other proposed filters.

UI demonstration

issue-53052-assets-dag-filter-demo-2026-08-02.mp4

The real local Airflow UI was validated with stable producer/consumer example data: 37 total Assets filtered to the 3 Assets related to asset_consumes_1_and_2, with reload persistence and Reset restoring the complete list.

Validation

• corepack pnpm@10 exec vitest run src/components/FilterBar/FilterBar.test.tsx src/pages/AssetsList/AssetsList.test.tsx — 5 tests passed
• Prettier check, ESLint, and TypeScript (tsc --noEmit) passed
• prek run --from-ref upstream/main --stage pre-commit passed
• prek run --from-ref upstream/main --stage manual passed, including production and development UI builds
• Independent standards and focused-scope reviews found no remaining actionable issues

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Was generative AI tooling used to co-author this PR?

• Yes — OpenAI Codex (GPT-5.6)

Generated-by: OpenAI Codex (GPT-5.6) following the guidelines

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Drafted-by: OpenAI Codex (GPT-5.6) (no human review before posting)