README: add a note on structured terminal sequence generation

Indicate the secondary value of the library as an abstraction over
escape sequences for terminal applications. Even without the high
performance rendering, the library is useful to provide semantic control
sequence generation.

Author: compnerd

README.md

@@ -82,6 +82,34 @@ let style = VTStyle(foreground: .rgb(red: 255, green: 100, blue: 50),
 buffer.write("Styled text", at: position, style: style)
 ```
 
+### Structured Terminal Control Sequences
+
+Beyond high-level UI rendering, VirtualTerminal provides a structured, type-safe API for formulating terminal escape sequences. Rather than hardcoding string literals like `"\033[31;1m"`, you express terminal commands using semantic Swift types.
+
+The `ControlSequence` enum covers ISO 6429/ECMA-48 compliant terminal operations:
+
+```swift
+import VirtualTerminal
+
+// Type-safe cursor positioning and styling
+await terminal <<< .CursorPosition(10, 20)
+await terminal <<< .SelectGraphicRendition([.bold, .foreground(.red)])
+await terminal <<< "Important text"
+await terminal <<< .SelectGraphicRendition([.reset])
+
+// Structured screen manipulation
+await terminal <<< .EraseDisplay(.EntireDisplay)
+await terminal <<< .SetMode([.DEC(.UseAlternateScreenBuffer)])
+```
+
+This approach offers:
+- **Semantic clarity**: Express intent with Swift types, not escape code memorization
+- **Compile-time validation**: Prevents malformed sequences and parameter errors
+- **Encoding abstraction**: Handles 7-bit vs 8-bit encoding automatically
+- **Composability**: Chain operations with fluent syntax using the `<<<` operator
+
+The library generates correct ANSI/VT100 escape sequences from these structured commands, making it both a UI toolkit and a robust terminal control sequence generator.
+
 ## Installation
 
 Add to your `Package.swift`: