Added:

- Modular builders for `gcc`, `clang`, `msvc`
- Platform-specific binary path generation (Linux/macOS/Windows)

Changed:
- Build configuration moved to `[build]` (`language`, `standard`, `compiler`)
- `dcr.toml` formatting now includes the `[build]` section
- Build uses built-in `debug/release` flags per compiler
- Build compiles all `*.c/*.cpp` files in `src/` into a single binary (no incremental build)
- Updated `dcr.toml` examples in documentation

src/core/builder/msvc.rs

@@ -0,0 +1,116 @@
+use crate::core::builder::BuildContext;
+use crate::platform;
+use std::fs;
+use std::process::Command;
+use std::time::Instant;
+
+pub fn build(ctx: &BuildContext) -> Result<f64, String> {
+    let compiler = if ctx.compiler.is_empty() {
+        "cl"
+    } else {
+        ctx.compiler
+    };
+    let start_time = Instant::now();
+    let mut cmd = Command::new(compiler);
+    let sources = collect_sources(ctx.language)?;
+
+    cmd.arg("/nologo");
+    match ctx.language.to_lowercase().as_str() {
+        "c" => {
+            cmd.arg("/TC");
+        }
+        "c++" | "cpp" | "cxx" => {
+            cmd.arg("/TP");
+        }
+        _ => {
+            return Err("Unsupported language".to_string());
+        }
+    }
+
+    if !ctx.standard.is_empty() {
+        let std_flag = msvc_standard_flag(ctx.language, ctx.standard)?;
+        cmd.arg(std_flag);
+    }
+
+    for flag in default_flags(ctx.profile) {
+        cmd.arg(flag);
+    }
+
+    for source in &sources {
+        cmd.arg(source);
+    }
+    cmd.arg(format!(
+        "/Fe:{}",
+        platform::bin_path(ctx.profile, ctx.project_name)
+    ));
+
+    match cmd.status() {
+        Ok(status) if status.success() => {
+            let elapsed = ((start_time.elapsed().as_secs_f64() * 100.0).trunc()) / 100.0;
+            Ok(elapsed)
+        }
+        Ok(_) => Err("Build failed".to_string()),
+        Err(err) => Err(format!("Build failed: {err}")),
+    }
+}
+
+fn collect_sources(language: &str) -> Result<Vec<String>, String> {
+    let lang = language.to_lowercase();
+    let mut sources = Vec::new();
+    let entries = fs::read_dir("./src").map_err(|err| format!("src dir error: {err}"))?;
+    for entry in entries {
+        let entry = entry.map_err(|err| format!("src dir error: {err}"))?;
+        let path = entry.path();
+        if !path.is_file() {
+            continue;
+        }
+        let ext = path
+            .extension()
+            .and_then(|v| v.to_str())
+            .unwrap_or("")
+            .to_lowercase();
+        let file = path.to_string_lossy().to_string();
+        let allowed = (lang == "c" && ext == "c")
+            || ((lang == "c++" || lang == "cpp" || lang == "cxx")
+                && (ext == "cpp" || ext == "cxx" || ext == "cc"));
+        if allowed {
+            sources.push(file);
+        }
+    }
+    sources.sort();
+    if sources.is_empty() {
+        return Err("No source files found in ./src".to_string());
+    }
+    Ok(sources)
+}
+
+fn msvc_standard_flag(language: &str, standard: &str) -> Result<String, String> {
+    let lang = language.to_lowercase();
+    let std = standard.to_lowercase();
+    if lang == "c" {
+        return match std.as_str() {
+            "c11" => Ok("/std:c11".to_string()),
+            "c17" => Ok("/std:c17".to_string()),
+            _ => Err("Unsupported C standard for MSVC".to_string()),
+        };
+    }
+    if lang == "c++" || lang == "cpp" || lang == "cxx" {
+        return match std.as_str() {
+            "c++11" => Ok("/std:c++11".to_string()),
+            "c++14" => Ok("/std:c++14".to_string()),
+            "c++17" => Ok("/std:c++17".to_string()),
+            "c++20" => Ok("/std:c++20".to_string()),
+            "c++23" => Ok("/std:c++latest".to_string()),
+            _ => Err("Unsupported C++ standard for MSVC".to_string()),
+        };
+    }
+    Err("Unsupported language".to_string())
+}
+
+fn default_flags(profile: &str) -> &'static [&'static str] {
+    match profile {
+        "release" => &["/O2", "/DNDEBUG"],
+        "debug" => &["/Od", "/Zi", "/W4", "/DDEBUG", "/Oy-"],
+        _ => &[],
+    }
+}