Make the FCC logo background transparent (#1257)

## Problem

The FCC mark is enclosed by a dark rounded-square tile. The tile
prevents the symbol from blending naturally with README, desktop, tray,
and menu-bar backgrounds.

## Changes

| Before | After |
| --- | --- |
| The three branches and terminal sit on a fixed dark tile. | The
branches and terminal sit on a transparent canvas. |
| Packaged and README artwork include the outer background. | SVG, PNG,
ICO, ICNS, and theme-aware README artwork retain only the FCC symbol. |
| The package version is 4.12.7. | The package version is 4.12.8. |

assets/free-claude-code-wordmark-dark.svg

@@ -1,7 +1,6 @@
 <svg xmlns="http://www.w3.org/2000/svg" width="1220" height="300" viewBox="0 0 1220 300" role="img" aria-labelledby="title">
   <title id="title">Free Claude Code</title>
   <g transform="translate(16 38) scale(.22)">
-    <rect x="32" y="32" width="960" height="960" rx="216" fill="#080b12"/>
     <g fill="none" stroke="#f97316" stroke-linecap="round" stroke-linejoin="round" stroke-width="56">
       <path d="M220 300h170c24 0 38 9 52 28l130 162c12 15 22 22 46 22h48"/>
       <path d="M220 512h446"/>

assets/free-claude-code-wordmark-light.svg

@@ -1,7 +1,6 @@
 <svg xmlns="http://www.w3.org/2000/svg" width="1220" height="300" viewBox="0 0 1220 300" role="img" aria-labelledby="title">
   <title id="title">Free Claude Code</title>
   <g transform="translate(16 38) scale(.22)">
-    <rect x="32" y="32" width="960" height="960" rx="216" fill="#080b12"/>
     <g fill="none" stroke="#f97316" stroke-linecap="round" stroke-linejoin="round" stroke-width="56">
       <path d="M220 300h170c24 0 38 9 52 28l130 162c12 15 22 22 46 22h48"/>
       <path d="M220 512h446"/>

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "free-claude-code"
-version = "4.12.7"
+version = "4.12.8"
 description = "Local proxy connecting coding agents to OpenAI-compatible AI providers"
 readme = "README.md"
 requires-python = ">=3.14.0"

src/free_claude_code/assets/app-icon.svg

@@ -1,5 +1,4 @@
 <svg xmlns="http://www.w3.org/2000/svg" width="1024" height="1024" viewBox="0 0 1024 1024">
-  <rect x="32" y="32" width="960" height="960" rx="216" fill="#080b12"/>
   <g fill="none" stroke="#f97316" stroke-linecap="round" stroke-linejoin="round" stroke-width="56">
     <path d="M220 300h170c24 0 38 9 52 28l130 162c12 15 22 22 46 22h48"/>
     <path d="M220 512h446"/>

uv.lock

@@ -620,7 +620,7 @@ wheels = [
 
 [[package]]
 name = "free-claude-code"
-version = "4.12.7"
+version = "4.12.8"
 source = { editable = "." }
 dependencies = [
     { name = "aiohttp" },