Fix: use scaler for scan-line rect height in SVG generator (JhaSourav07#1599)

## Description

Fixes JhaSourav07#1597 

This PR fixes an SVG rendering issue where the scan-line rectangle
height was using the raw size scale factor (`sf`) instead of the
renderer scaler.

Previously, the scan-line height was rendered as:

```ts
height="${sf}"
```

This could produce fractional values (e.g. `0.667`, `1.333`) for
non-default badge sizes, leading to inconsistent rendering across
browsers and SVG viewers.

### Changes Made

* Replaced `height="${sf}"` with `height="${s(1)}"` in:

  * `generateSVG()`
  * `generateAutoThemeSVG()`
* Ensured scan-line height is calculated using the renderer scaler and
expressed in pixel units.
* Aligned scan-line rendering behavior with the `notFound` renderer
implementation.

### Result

* Consistent scan-line rendering across all badge sizes.
* Eliminates fractional height values that could cause visual artifacts
or disappearing scan lines.
* Maintains existing animation and theme behavior.

## Pillar

* [ ] 🎨 Pillar 1 — New Theme Design
* [x] 📐 Pillar 2 — Geometric SVG Improvement
* [ ] 🕐 Pillar 3 — Timezone Logic Optimization
* [ ] 🛠️ Other (Bug fix, refactoring, docs)

Manual verification performed:

* Generated badges using `size=small`, `size=medium`, and `size=large`
* Confirmed scan-line height is generated via `s(1)`
* Verified scan-line renders consistently across sizes
* Confirmed animations and CSS variables remain unchanged

## Checklist before requesting a review:

* [x] I have read the `CONTRIBUTING.md` file.
* [x] I have tested these changes locally
(`localhost:3000/api/streak?user=YOUR_USERNAME`).
* [x] I have run `npm run format` and `npm run lint` locally and
resolved all errors (CI will fail otherwise).
* [x] My commits follow the Conventional Commits format (e.g.,
`feat(themes): ...`, `fix(calculate): ...`).
* [ ] I have updated `README.md` if I added a new theme or URL
parameter.
* [x] I have starred the repo.
* [x] I have made sure that I have only one commit to merge in this PR.
* [x] The SVG output matches the CommitPulse "premium quality" aesthetic
standard (no raw elements, smooth animations, correct fonts).
* [ ] (Recommended) I joined the CommitPulse Discord community for
contributor discussions, mentorship, and faster PR support.

Author: JhaSourav07

lib/svg/generator.ts

@@ -337,7 +337,7 @@ function renderFooter(
     x="${s(100)}"
     y="${s(80)}"
     width="${s(400)}"
-    height="${sf}"
+    height="${s(1)}"
     class="cp-accent-fill scan-line"
     fill-opacity="0.3"
     style="--scan-speed: ${params.speed || '8s'}; --scan-start: ${s(0)}px; --scan-end: ${s(240)}px;"
@@ -588,7 +588,7 @@ ${
     x="${s(100)}"
     y="${s(80)}"
     width="${s(400)}"
-    height="${sf}"
+    height="${s(1)}"
     class="cp-accent-fill scan-line"
     fill-opacity="0.3"
     style="--scan-speed: ${params.speed || '8s'}; --scan-start: ${s(0)}px; --scan-end: ${s(240)}px;"