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/build.rs

@@ -1,100 +1,4 @@
-use std::env;
-use std::path::PathBuf;
-use std::process::Command;
-
 fn main() {
-    // Only build Vision bridge on macOS
-    if env::var("CARGO_CFG_TARGET_OS").unwrap() != "macos" {
-        return;
-    }
-
-    println!("cargo:rerun-if-changed=vision-bridge/Sources/VisionBridge/VisionOCR.swift");
-    println!("cargo:rerun-if-changed=vision-bridge/Sources/VisionBridge/VisionBridge.h");
-    println!("cargo:rerun-if-changed=vision-bridge/Package.swift");
-
-    let manifest_dir = PathBuf::from(env::var("CARGO_MANIFEST_DIR").unwrap());
-    let vision_bridge_dir = manifest_dir.join("vision-bridge");
-
-    // Build Swift package
-    println!("cargo:warning=Building VisionBridge Swift package...");
-    let build_status = Command::new("swift")
-        .args(&["build", "-c", "release"])
-        .current_dir(&vision_bridge_dir)
-        .status()
-        .expect("Failed to build Swift package");
-
-    if !build_status.success() {
-        panic!("Swift build failed");
-    }
-
-    // Find the built library
-    let lib_path = vision_bridge_dir
-        .join(".build/release")
-        .canonicalize()
-        .expect("Failed to find .build/release directory");
-
-    // Copy the dylib to the output directory so it can be found at runtime
-    let target_dir = manifest_dir
-        .parent()
-        .unwrap()
-        .parent()
-        .unwrap()
-        .join("target");
-    let profile = env::var("PROFILE").unwrap_or_else(|_| "debug".to_string());
-
-    // Determine the actual target directory (could be llvm-cov-target or regular target)
-    let target_dir_name =
-        env::var("CARGO_TARGET_DIR").unwrap_or_else(|_| target_dir.to_string_lossy().to_string());
-    let actual_target_dir = PathBuf::from(&target_dir_name);
-    let output_dir = actual_target_dir.join(&profile);
-
-    let dylib_src = lib_path.join("libVisionBridge.dylib");
-    let dylib_dst = output_dir.join("libVisionBridge.dylib");
-
-    // Create output directory if it doesn't exist
-    std::fs::create_dir_all(&output_dir).expect(&format!(
-        "Failed to create output directory {}",
-        output_dir.display()
-    ));
-
-    std::fs::copy(&dylib_src, &dylib_dst).expect(&format!(
-        "Failed to copy dylib from {} to {}",
-        dylib_src.display(),
-        dylib_dst.display()
-    ));
-
-    println!(
-        "cargo:warning=Copied libVisionBridge.dylib to {}",
-        dylib_dst.display()
-    );
-
-    // Re-sign the dylib with ad-hoc signature to fix code signing issues on Apple Silicon
-    // This is necessary because incremental compilation can invalidate signatures
-    let codesign_status = Command::new("codesign")
-        .args(&["-f", "-s", "-", dylib_dst.to_str().unwrap()])
-        .status();
-
-    if let Ok(status) = codesign_status {
-        if !status.success() {
-            println!("cargo:warning=Failed to codesign libVisionBridge.dylib (non-fatal)");
-        }
-    }
-
-    // Add rpath so the dylib can be found at runtime
-    println!("cargo:rustc-link-arg=-Wl,-rpath,@executable_path");
-    println!("cargo:rustc-link-arg=-Wl,-rpath,@loader_path");
-    println!("cargo:rustc-link-search=native={}", lib_path.display());
-    println!("cargo:rustc-link-lib=dylib=VisionBridge");
-
-    // Link required frameworks
-    println!("cargo:rustc-link-lib=framework=Vision");
-    println!("cargo:rustc-link-lib=framework=AppKit");
-    println!("cargo:rustc-link-lib=framework=Foundation");
-    println!("cargo:rustc-link-lib=framework=CoreGraphics");
-    println!("cargo:rustc-link-lib=framework=CoreImage");
-
-    println!(
-        "cargo:warning=VisionBridge built successfully at {}",
-        lib_path.display()
-    );
+    // No build-time dependencies required
+    // VisionBridge OCR has been removed
 }