Clean up code. Reorganize files. Port stuff from other branches. + more

This turns the project into a monorepo using pnpm workspaces,
dramatically simplifying the build process. It also fixes a lot of bugs
and just generally makes the codebase a lot cleaner.

packages/solver/build.zig

@@ -0,0 +1,46 @@
+const std = @import("std");
+
+pub fn build(b: *std.Build) void {
+    const optimize = b.standardOptimizeOption(.{});
+    const target = b.standardTargetOptions(.{});
+
+    // solver
+    const solver_mod = b.addModule("solver", .{
+        .root_source_file = b.path("src/solver.zig"),
+        .optimize = optimize,
+        .target = target,
+    });
+
+    const solver_exe = b.addExecutable(.{
+        .name = "solver",
+        .root_module = solver_mod,
+    });
+
+    if (target.result.cpu.arch == .wasm32) {
+        solver_exe.entry = .disabled;
+        solver_exe.rdynamic = true;
+        solver_exe.link_gc_sections = true;
+        solver_exe.lto = .full;
+    }
+
+    b.installArtifact(solver_exe);
+
+    // validator
+    const validator_mod = b.addModule("validator", .{
+        .root_source_file = b.path("src/validator.zig"),
+        .optimize = optimize,
+        .target = target,
+    });
+
+    const validator_exe = b.addExecutable(.{
+        .name = "validator",
+        .root_module = validator_mod,
+    });
+
+    if (target.result.cpu.arch == .wasm32) {
+        validator_exe.entry = .disabled;
+        validator_exe.rdynamic = true;
+    }
+
+    b.installArtifact(validator_exe);
+}