Floating promises: add `void` to all unhandled refreshHighlightData() calls
in callbacks and event listeners; extract processFilePicker() to fix the async
event listener returning a Promise where void was expected.
Inline styles: replace all style.cssText and setAttribute('style') with CSS
classes (pseudobs-hidden-input, pseudobs-legend-*, pseudobs-suggestions-*,
pseudobs-occ-*, pseudobs-disabled-input) across OccurrencesModal, RuleModal,
QuickPseudonymizeModal, EditRuleModal, and main.ts.
Settings headings: replace all createEl('h2'/'h3') with new Setting().setHeading()
in PseudObsSettingTab (5 headings).
Sentence case: fix linter-flagged occurrences (placeholder text, legend labels,
button text); 4 residual occurrences on legitimate proper nouns (Baptiste Coulmont,
Jefferson, ICOR, Synology Drive) left for human reviewer.
