Build TercihAI MVP: landing page, YÖK Atlas data pipeline, rank-based results

- Add product vision/market research doc (VISION.md)
- Set up shadcn/ui (radix + nova preset) with blue/orange theme, Outfit + Work Sans fonts
- Landing page: hero with rank input, problem/steps sections, comparison table, FAQ
- Data pipeline: CSV archive ingest (2021-2024) + live YÖK Atlas API refresh (2025)
  into SQLite (npm run ingest / refresh); zeros normalized to NULL
- /sonuc page: hayal/dengeli/garanti buckets by COALESCE(sira2025, sira2024),
  score-type switcher, 2024→2025 trend indicators
- Add ui-ux-pro-max and shadcn agent skills, shadcn MCP config, launch.json

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.agents/skills/migrate-radix-to-base/class-mapping.md

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+# Class-string rewrites (layer 2)
+
+Apply these across ALL class strings (className, cva definitions, cn calls),
+including app code. They are safe, mechanical rewrites.
+
+## Data-attribute selectors
+
+| Radix pattern | Base UI pattern |
+|---|---|
+| `data-[state=open]:` | `data-open:` |
+| `data-[state=closed]:` | `data-closed:` |
+| `data-[state=checked]:` | `data-checked:` |
+| `data-[state=unchecked]:` | `data-unchecked:` |
+| `data-[state=active]:` (tabs) | `data-active:` |
+| `data-[state=on]:` (toggle) | `data-pressed:` |
+| `data-[highlighted]:` | `data-highlighted:` (unchanged) |
+| `data-[disabled]:` | `data-disabled:` (unchanged) |
+| `data-[side=...]:` | `data-[side=...]:` (unchanged, still parameterized) |
+| `group-data-[state=open]` / `peer-data-[state=open]` | `group-data-open` / `peer-data-open` |
+| submenu trigger open marker `data-[state=open]:` | `data-popup-open:` |
+
+## Animation idiom
+
+Radix (tw-animate/keyframes):
+`data-[state=open]:animate-in data-[state=open]:fade-in-0 data-[state=closed]:animate-out data-[state=closed]:fade-out-0`
+
+Base UI (transition + starting/ending styles):
+`transition-[opacity,transform] data-starting-style:opacity-0 data-ending-style:opacity-0` (plus translate/scale equivalents).
+
+Do not translate animate-in/out utilities 1:1; restate the intent with
+`data-starting-style:` / `data-ending-style:` transitions. When the original
+uses per-side slide classes, keep the `data-[side=...]` or
+`data-[swipe-direction=...]` parameterization.
+
+## CSS variables
+
+| Radix var | Base UI var |
+|---|---|
+| `--radix-<comp>-content-transform-origin` | `--transform-origin` |
+| `--radix-<comp>-content-available-height` | `--available-height` |
+| `--radix-<comp>-content-available-width` | `--available-width` |
+| `--radix-<comp>-trigger-width` | `--anchor-width` |
+| `--radix-<comp>-trigger-height` | `--anchor-height` |
+| `--radix-accordion-content-height` | `--accordion-panel-height` |
+| `--radix-collapsible-content-height` | `--collapsible-panel-height` |
+| `--radix-navigation-menu-viewport-height/width` | `--positioner-height` / `--positioner-width` |
+
+## Element changes kill pseudo-class variants
+
+When a part's rendered element changes from a form control to a generic
+element (checkbox/switch/radio Roots render `<span>` in Base UI), `disabled:`
+and `:disabled` Tailwind variants become dead code. Replace them with
+`data-disabled:` equivalents. (Note: the shadcn base registry's checkbox
+still carries the dead `disabled:*` classes; treat that as an upstream quirk,
+not a pattern to copy.)
+
+## Disabled-state hooks
+
+Some Base UI triggers surface disabled state as `aria-disabled` rather than
+the `disabled` attribute (accordion trigger, tabs tab). Where the radix code
+used `disabled:opacity-50`, add or substitute `aria-disabled:opacity-50`
+according to the wrapper's reference file.