Remove VisionBridge OCR (unused)

VisionBridge was a Swift library for Apple Vision OCR that was built
every compile but never actually used by any g3 tool.

Removed:
- vision-bridge/ Swift package directory
- src/ocr/ module (vision.rs, tesseract.rs, mod.rs)
- OCR methods from ComputerController trait
- OCR-related code from platform implementations
- TextLocation type (no longer needed)
- test_vision.rs example

Simplified:
- build.rs (now empty, no Swift compilation)
- MacOSController (no longer holds OCR engine)
- LinuxController and WindowsController (stub implementations)

Build time improvement: No more 'Building VisionBridge Swift package...'
messages on every compile.

crates/g3-computer-control/examples/test_vision.rs

@@ -1,92 +0,0 @@
-use anyhow::Result;
-use g3_computer_control::ocr::{DefaultOCR, OCREngine};
-
-#[tokio::main]
-async fn main() -> Result<()> {
-    println!("🧪 Testing Apple Vision OCR");
-    println!("===========================\n");
-
-    // Initialize OCR engine
-    println!("📦 Initializing OCR engine...");
-    let ocr = DefaultOCR::new()?;
-    println!("✅ OCR engine: {}\n", ocr.name());
-
-    // Check if test image exists
-    let test_image = "/tmp/safari_test.png";
-    if !std::path::Path::new(test_image).exists() {
-        println!("⚠️  Test image not found: {}", test_image);
-        println!("   Creating a screenshot...");
-
-        let status = std::process::Command::new("screencapture")
-            .arg("-x")
-            .arg("-R")
-            .arg("0,0,1200,800")
-            .arg(test_image)
-            .status()?;
-
-        if !status.success() {
-            anyhow::bail!("Failed to create screenshot");
-        }
-
-        println!("✅ Screenshot created\n");
-    }
-
-    // Run OCR
-    println!("🔍 Running Apple Vision OCR on {}...", test_image);
-    let start = std::time::Instant::now();
-    let locations = ocr.extract_text_with_locations(test_image).await?;
-    let duration = start.elapsed();
-
-    println!("✅ OCR completed in {:.3}s\n", duration.as_secs_f64());
-
-    // Display results
-    println!("📊 Results:");
-    println!("   Found {} text elements\n", locations.len());
-
-    if locations.is_empty() {
-        println!("⚠️  No text found in image");
-    } else {
-        println!("   Top 20 results:");
-        println!(
-            "   {:<4} {:<40} {:<15} {:<12} {:<8}",
-            "#", "Text", "Position", "Size", "Conf"
-        );
-        println!("   {}", "-".repeat(85));
-
-        for (i, loc) in locations.iter().take(20).enumerate() {
-            let text = if loc.text.len() > 37 {
-                format!("{}...", &loc.text[..37])
-            } else {
-                loc.text.clone()
-            };
-
-            println!(
-                "   {:<4} {:<40} ({:>4},{:>4})    {:>4}x{:<4}  {:.2}",
-                i + 1,
-                text,
-                loc.x,
-                loc.y,
-                loc.width,
-                loc.height,
-                loc.confidence
-            );
-        }
-
-        if locations.len() > 20 {
-            println!("\n   ... and {} more", locations.len() - 20);
-        }
-
-        // Performance comparison
-        println!("\n📈 Performance:");
-        println!("   OCR Speed: {:.3}s", duration.as_secs_f64());
-        println!("   Text elements: {}", locations.len());
-        println!(
-            "   Avg per element: {:.1}ms",
-            duration.as_millis() as f64 / locations.len() as f64
-        );
-    }
-
-    println!("\n✅ Test complete!");
-
-    Ok(())
-}