Create and promote components

[fedorovvvv]

Promote template/src/shared/ui to a full shadcn-svelte primitive set (26 components) using bits-ui (already in deps) + CSS variables (no Tailwind). Same shape as existing Button / Select.

Backed by PRD-018 + RFC-016 (Standard depth).

Components

shadcn-svelte reference: https://www.shadcn-svelte.com/docs/components

• toggle, toggle group, button group, badge, tooltip, popover, toaster, switch, input, input group, field, label, tabs, separator, skeleton, spinner, collapsible, alert, accordion, checkbox, radio, radio group, command, item, progress, card, slider

Plan

1. Create all 26 primitives in template/src/shared/ui/ — broken into 7 groups by family.
2. Integrate / replace ad-hoc styles in widgets/* (1 group).
3. Visual smoke in Chrome.

Sub-issues

• [#68 / 1] Visual atoms — Badge, Separator, Skeleton, Spinner, Card, Alert, Progress #72 — Group 1: Visual atoms (badge, separator, skeleton, spinner, card, alert, progress)
• [#68 / 2] Form basics — Label, Input, Field, InputGroup #73 — Group 2: Form basics (label, input, field, input-group)
• [#68 / 3] Toggles — Toggle, ToggleGroup, ButtonGroup, Switch, Checkbox, Slider #74 — Group 3: Toggles (toggle, toggle-group, button-group, switch, checkbox, slider)
• [#68 / 4] Radio — Radio, RadioGroup #75 — Group 4: Radio (radio, radio-group)
• [#68 / 5] Disclosure — Tabs, Collapsible, Accordion #76 — Group 5: Disclosure (tabs, collapsible, accordion)
• [#68 / 6] Overlays — Tooltip, Popover, Toaster #77 — Group 6: Overlays (tooltip, popover, toaster)
• [#68 / 7] Command — Command, Item #78 — Group 7: Command (command, item)
• [#68 / 8] Integrate primitives + Chrome smoke #79 — Group 8: Integrate + Chrome smoke

Branch: feature/issue-68-shadcn-components → PR into develop.