revert(icons): drop the glyph outlines, keep only the terminal's smaller size

The hairline outline I added to the colored tab glyphs reads as a thick stroke
in the live instance, so it goes: the glyphs stay exactly as the icon set draws
them, tinted only through the wrapper's token. What the feedback actually asked
for was the terminal SIZE, and that is all that remains — it renders a step
down (0.85x, floor 10px) because the VSCodicon terminal is a wide filled
rectangle that read heavier than its neighbours.

tests/builtins.spec.ts keeps pinning both readings (tasks = layers, terminal =
the shrunk VscTerminal with no style override), so the assertion now also
guards against an outline creeping back in.

tests/builtins.spec.ts

@@ -257,15 +257,14 @@ describe('built-in tab registrations', () => {
     expect(glyphOf('git')).toBe(VscGitCommit)
     expect(glyphOf('sidechat')).toBe(VscCommentDiscussion)
     expect(glyphOf('browser')).toBe(VscGlobe)
-    // The terminal glyph is the widest in the set: it renders a step down from
-    // the strip's size and keeps a hairline outline so it matches the plugin's
-    // own drawn chrome instead of reading as a heavy filled block.
+    // The terminal glyph is the widest in the set, so it renders a step down
+    // from the strip's size. No outline: the glyphs stay exactly as the icon
+    // set draws them, only tinted through the wrapper's token.
     const wrapper = iconOf('terminal') as ReactElement<{ children?: ReactElement }>
     const terminal = wrapper.props.children as ReactElement<{ size?: number; style?: Record<string, unknown> }>
     expect(terminal.type).toBe(VscTerminal)
     expect(terminal.props.size).toBeLessThan(14)
-    expect(terminal.props.style?.strokeWidth).toBe(1)
-    expect(terminal.props.style?.vectorEffect).toBe('non-scaling-stroke')
+    expect(terminal.props.style).toBeUndefined()
   })
 })