feat: add template inheritance (extends/block) support

- ViewEngine now supports extends and named blocks
- Each route gets exclusive cached AST (no shared parent layouts)
- Fix iteration over struct arrays in each loops
- Add demo app with full e-commerce layout using extends
- Serve static files from public folder
- Bump version to 0.3.0

build.zig

@@ -3,10 +3,19 @@ const std = @import("std");
 pub fn build(b: *std.Build) void {
     const target = b.standardTargetOptions(.{});
     const optimize = b.standardOptimizeOption(.{});
+    // Get cache.zig dependency
+    const cache_dep = b.dependency("cache", .{
+        .target = target,
+        .optimize = optimize,
+    });
+
     const mod = b.addModule("pugz", .{
         .root_source_file = b.path("src/root.zig"),
         .target = target,
         .optimize = optimize,
+        .imports = &.{
+            .{ .name = "cache", .module = cache_dep.module("cache") },
+        },
     });
 
     // Creates an executable that will run `test` blocks from the provided module.
@@ -17,6 +26,32 @@ pub fn build(b: *std.Build) void {
     // A run step that will run the test executable.
     const run_mod_tests = b.addRunArtifact(mod_tests);
 
+    // Source file unit tests (lexer, parser, runtime, etc.)
+    const source_files_with_tests = [_][]const u8{
+        "src/lexer.zig",
+        "src/parser.zig",
+        "src/runtime.zig",
+        "src/template.zig",
+        "src/codegen.zig",
+        "src/strip_comments.zig",
+        "src/linker.zig",
+        "src/load.zig",
+        "src/error.zig",
+        "src/pug.zig",
+    };
+
+    var source_test_steps: [source_files_with_tests.len]*std.Build.Step.Run = undefined;
+    inline for (source_files_with_tests, 0..) |file, i| {
+        const file_tests = b.addTest(.{
+            .root_module = b.createModule(.{
+                .root_source_file = b.path(file),
+                .target = target,
+                .optimize = optimize,
+            }),
+        });
+        source_test_steps[i] = b.addRunArtifact(file_tests);
+    }
+
     // Integration tests - general template tests
     const general_tests = b.addTest(.{
         .root_module = b.createModule(.{
@@ -62,6 +97,10 @@ pub fn build(b: *std.Build) void {
     test_step.dependOn(&run_general_tests.step);
     test_step.dependOn(&run_doctype_tests.step);
     test_step.dependOn(&run_check_list_tests.step);
+    // Add source file tests
+    for (&source_test_steps) |step| {
+        test_step.dependOn(&step.step);
+    }
 
     // Individual test steps
     const test_general_step = b.step("test-general", "Run general template tests");
@@ -72,6 +111,9 @@ pub fn build(b: *std.Build) void {
 
     const test_unit_step = b.step("test-unit", "Run unit tests (lexer, parser, etc.)");
     test_unit_step.dependOn(&run_mod_tests.step);
+    for (&source_test_steps) |step| {
+        test_unit_step.dependOn(&step.step);
+    }
 
     const test_check_list_step = b.step("test-check-list", "Run check_list template tests");
     test_check_list_step.dependOn(&run_check_list_tests.step);
@@ -94,4 +136,23 @@ pub fn build(b: *std.Build) void {
     run_bench.setCwd(b.path("."));
     const bench_step = b.step("bench", "Run benchmark");
     bench_step.dependOn(&run_bench.step);
+
+    // Test includes example
+    const test_includes_exe = b.addExecutable(.{
+        .name = "test-includes",
+        .root_module = b.createModule(.{
+            .root_source_file = b.path("examples/test_includes.zig"),
+            .target = target,
+            .optimize = optimize,
+            .imports = &.{
+                .{ .name = "pugz", .module = mod },
+            },
+        }),
+    });
+    b.installArtifact(test_includes_exe);
+
+    const run_test_includes = b.addRunArtifact(test_includes_exe);
+    run_test_includes.setCwd(b.path("."));
+    const test_includes_step = b.step("test-includes", "Test include/mixin rendering");
+    test_includes_step.dependOn(&run_test_includes.step);
 }