Category picker doesn't render category-specific icons (all show generic tag)

**What happens:** On the "Your Interests" picker (3-to-5 category selection, shown post-signup / on the personalize-feed flow), every category chip renders the **same generic price-tag outline icon** to the left of the label — Social & Networking, Sports & Outdoors, Music & Arts, Tech & Science, Food & Drinks, Health & Wellness, etc. all show the identical icon. **Expected:** Each category should render its own visual icon — e.g. music note for Music & Arts, fork/cutlery for Food & Drinks, ball for Sports & Outdoors, heart/cross for Health & Wellness, paw for Pets & Animals, plane/compass for Travel & Adventure, etc. This is a discoverability + scanability feature — users recognize categories visually before reading the label. **Where it shows up:** - Post-signup interest picker (the screen titled "Your Interests — Pick 3 to 5 topics to personalize your feed") - Likely the same component is reused on settings → interests (please verify), and possibly anywhere else categories are listed with icons **Likely cause:** the category rendering component is either (a) hard-coding a default `<Icon name="tag" />` for every category instead of reading the icon from the category record, or (b) the backend `GET /v1/categories` payload is missing the per-category `icon` field, or (c) the icon field exists in the API response but the frontend isn't reading it / can't find an icon component for the value. The backend has 19 categories (per the perf audit notes) — verify each row has an `icon` value before assuming this is a frontend-only bug. **Repro:** 1. Sign up or visit the interests picker as a logged-in user. 2. Observe every category chip displays the same tag-outline icon. 3. Expected: each chip's icon should match the category theme. **Selected state:** the active (selected) chips also show the same generic tag icon, just in the active color — so the bug is independent of the selected/unselected state, it's at the icon-render level for every chip.