feat(frontend): collapsible rule options, preset pills, selection & label updates

[theodubus]

Motivation

• Simplify the rules UI by hiding less-frequent options in a single collapsible panel and make presets visually consistent with options.
• Replace ambiguous kind badges (exact / regex) with a single, clearer label and localize selection labels.
• Add support for creating rules from PDF text selection and send selection rectangles to the backend for precise redaction.

Description

• Moved rule options into a collapsible > Options block under the search bar and applied the same pattern to the edit modal by wrapping RuleOptionsRow in a <details>/<summary> (changes in RulesSection.tsx and EditRuleModal.tsx).
• Replaced preset checkboxes with clickable pill buttons and added PresetPill so presets behave like the other pill controls (changes in PresetsSection.tsx and styling).
• Unified list labels so exact/regex rules show as Requête/Request and selections show as Sélection/Selection by updating kindLabel and locale files (fr.json / en.json).
• Implemented page selection capture in PdfViewer that computes scaled UiRect[] for the selection, passes selection info up to App, and supports adding a selection rule; added UiRect / selection rule type and included rects in the API payload by adding RectInput and rects support to api.ts and types/uiRules.ts.
• Pulled file controls into the top band (HeaderBar) with the selected file name and drag-and-drop / hidden file input behavior in App.tsx; also removed the duplicated hint fallback from the right panel by simplifying ResultPanel to not show the standalone hint.
• Various UI/UX and preview enhancements in PdfViewer: preview highlight drawing refactor, preset-match highlighting (basic), preserving page scale when computing selection rects, and improved rule list/action button styling (RulesList.tsx, PdfViewer.tsx, styles.css).

Testing

• Built the frontend with cd frontend && npm run build, and the production build completed successfully. ✅
• Started the dev server with cd frontend && npm run dev -- --host 0.0.0.0 --port 4173, Vite reported ready. ✅
• Captured a UI screenshot using a Playwright script to validate the new collapsible options, preset pills and selection UI (artifact produced). ✅

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Codex Task