feat(collection): tap a tag chip to filter the Collection to that tag (#414)

[ibanner56]

Closes #414.

What

Tapping a tag chip where a user reads a dance's tags — the dance detail/summary screen and Collection list rows — now switches to the Collection list and filters it to that tag, so a caller can quickly find every dance sharing it.

Approach

• New CollectionFilterController / CollectionFilterScope (app/lib/src/data/collection_filter_scope.dart), provided in main.dart's MaterialApp.builder chain — above the root Navigator — mirroring the existing CollectionRefreshScope, so pushed detail routes can reach it.
• AppShell subscribes and, on a request, switches to the Collection tab (index 0) and pops to the list root.
• DanceListScreen applies the filter through the existing FacetSelections.tagIds / TagFilter facet — no core changes, no second filtering system.
• Tag chips become tappable ActionChips: on the detail screen (guarded to non-preview) and on list rows (opt-in via onTagTap, so the Programs dance picker is unaffected).

Replace vs. add — decision: REPLACE

A tap clears prior FTS/facets/advanced filters and applies a clean single-tag filter. Arriving from a detail screen with unknown prior filter state, a predictable "show everything with this tag" result — that the user can then clear — matches the issue intent better than silently AND-ing onto hidden filters. The active filter stays visible (Filters "(N active)" badge + selected tag facet chip) and clearable (Clear filters / untoggle).

Security (OWASP)

No new untrusted-input surface. Tag ids originate from the local DB and flow into the existing parameterized TagFilter (matched by id, never by text). Tag names are display-only (Text), so a tag name with SQL/regex/emoji/RTL characters is safe — covered by a dedicated test.

Tests

New app/test/tag_filter_navigation_test.dart (6 tests): narrow pushed-detail nav, wide embedded-pane, clearable filter, list-row in-place filter, a tag with zero other dances, and a special-character tag name.

Gates

• fvm dart format . — clean
• fvm flutter analyze (app) — No issues found; fvm dart analyze (core) — No issues found
• Core fvm dart test — 1798 passed (~4 skipped)
• App fvm flutter test — 1651 passed

Co-authored-by: Copilot App 223556219+Copilot@users.noreply.github.com

[Copilot]

Pull request overview

Adds a cross-screen “tap a tag → jump to Collection filtered by that tag” interaction by introducing an app-level filter coordinator and wiring tag chips in both dance detail and collection rows to publish filter requests that the shell/list react to.

Changes:

• Introduces CollectionFilterController/CollectionFilterScope to broadcast “filter Collection by tag” requests across routes.
• Makes tag chips tappable (ActionChip) on dance detail and (optionally) on list rows, applying the existing tag facet filter.
• Adds widget tests covering narrow/wide navigation, clearability, in-place row filtering, and special-character tag names.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
app/test/tag_filter_navigation_test.dart	New widget tests for tag-tap navigation/filtering flows across layouts.
app/lib/src/widgets/dance_list_tile.dart	Adds onTagTap and renders tag chips as ActionChip when interactive.
app/lib/src/search/dance_detail_data.dart	Adds (id, name) tag pairs to detail data for id-based filtering.
app/lib/src/search/collection_data.dart	Adds (id, name) tag pairs to list entries for id-based filtering.
app/lib/src/screens/dance_list_screen.dart	Subscribes to filter requests and applies a single-tag facet filter by replacing the current query.
app/lib/src/screens/dance_detail_screen.dart	Makes detail tag chips publish filter requests via the new scope (non-preview only).
app/lib/src/screens/app_shell.dart	Listens for filter requests to switch to Collection and pop pushed routes so the filtered list is visible.
app/lib/src/models/dance_list_entry.dart	Adds (id, name) tag pairs for list-row chip rendering/filtering.
app/lib/src/data/collection_filter_scope.dart	New app-level coordinator (controller + inherited scope) for tag filter requests.
app/lib/main.dart	Provides CollectionFilterScope above the root navigator via MaterialApp.builder.

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