## What
Adds **saved filters** on the transactions page so users can name a set
of filters and reuse them later. The whole feature is gated behind a new
\`transaction-analysis\` Pennant feature flag (off by default).
## Why
Reusing the same filter combinations (e.g. "Japan trip", "Utilities") is
currently manual every time. This ports the saved-filters work from the
\`analysis-page\` branch, scoped down to **only** the transactions page
— the analysis screen and unrelated query changes from that branch are
intentionally left out.
## Changes
**Feature flag**
- \`App\Features\TransactionAnalysis\` — class-based flag, resolves
\`false\` by default.
- Shared to the frontend as \`features.transactionAnalysis\` and added
to the \`Features\` type.
**Backend (saved filters)**
- \`SavedFilter\` model (UUID, \`filters\` json cast, user belongsTo) +
migration + factory.
- \`Api\SavedFilterController\` — user-scoped index/store/update/destroy
under \`/api/saved-filters\`, ownership enforced with \`abort_unless\`.
- \`StoreSavedFilterRequest\` / \`UpdateSavedFilterRequest\` — name
unique per user, snake_case filter rules.
**Frontend**
- \`transaction-filter-serialization.ts\` —
serialize/deserialize/fingerprint between UI filter state and the
persisted snake_case shape.
- \`SavedFilters\` dropdown — load/save/update/delete with active +
dirty indicators.
- Integrated into the filter bar via an opt-in \`enableSavedFilters\`
prop, so it renders **only** on the transactions page (budgets/accounts
reuse the same component and stay unchanged). Render is also gated by
the feature flag.
**Filter bar UX**
- Split search + filters + saved searches onto their own row, separate
from the actions row (Categorize / Add transactions / columns), which
were getting cramped.
- On mobile, the text search moves into the filters popover.
## Reviewer notes
- Backend endpoints are **not** flag-gated; only the UI is, per the
request.
- Two-layer scoping: page opt-in prop **and** feature flag — flag off
means no UI anywhere.
- Translation keys fall back to the key (English); \`es.json\` entries
not added, matching the source branch.
## Testing
- \`tests/Feature/SavedFilterTest.php\` — 9 passing (auth, per-user
listing/uniqueness, ownership on update/delete).
- Pint, Prettier, ESLint clean. No new TypeScript errors introduced.