Frontend: split monolithic single-file components into template/style/logic

[pcastelo]

Problem

6 frontend components are monolithic single-file components with inline templates (HTML), styles (CSS), and business logic mixed together. Largest: threescale-explorer.component.ts at 680 LOC.

Components to refactor

• threescale-explorer.component.ts (680 LOC) — extract template, styles, and API logic to service
• chat.component.ts (507 LOC) — extract template, styles, and chat service
• dashboard.component.ts (473 LOC) — extract template, styles, and data service
• audit-log.component.ts (351 LOC) — extract template, styles
• settings.component.ts (316 LOC) — extract template, styles, and CRUD service

Acceptance criteria

• Each component has separate .html, .scss, and .ts files
• Business logic extracted to dedicated services
• No component exceeds 200 LOC (excluding imports)
• Deduplicate common CSS patterns (.page-header, .container, buttons) into shared styles