fix(terminal): Line height, colour palette and tab names (#141)

* fix(terminal): Line height, colour palette and tab names

- Line height: with "Use editor font" the terminal took the editor's roomier
  line height (about 1.33 cells), stretching ASCII art and box drawing. It now
  always uses Settings › Tools › Terminal › Line height (default 1.0); that
  field moves out of the "Use editor font" group since it applies either way.
- Colours: the terminal gets its own --terminal-ansi-* palette (the light and
  Darcula terminal colours); the Run console keeps --ansi-*. High-contrast and
  palette themes keep their console colours. Colours below a 4.5:1 contrast
  with the background are adjusted (xterm's minimumContrastRatio), so yellow
  stays readable on white.
- Tab names: tabs keep their default name ("Local", "Local (2)") at the prompt
  and show the title a program sets only while a command runs. Shell
  integration now marks command start and end (OSC 133 C / D) for zsh,
  bash 4.4+ (PS0) and fish.

* fix(themes): Document the terminal ANSI palette for theme plugins

The --terminal-ansi-* tokens belong in a theme's editor colour scheme, like
--ansi-*. The theme plugin template sets them and the token reference lists them.

src/features/settings/pages/tools.tsx

@@ -264,16 +264,16 @@ function TerminalFont() {
             aria-label="Terminal font size"
           />
         </Row>
-        <Row label="Line height">
-          <NumberInput
-            value={lineHeight}
-            onChange={setLineHeight}
-            {...L.terminalLineHeight}
-            step={0.1}
-            aria-label="Terminal line height"
-          />
-        </Row>
       </Indented>
+      <Row label="Line height">
+        <NumberInput
+          value={lineHeight}
+          onChange={setLineHeight}
+          {...L.terminalLineHeight}
+          step={0.1}
+          aria-label="Terminal line height"
+        />
+      </Row>
       <Row label="Fallback font" htmlFor={fallbackId} hint="Used for characters the main font lacks.">
         <Input
           id={fallbackId}