Add addUserText helper; update all call sites

Conversation.addUserMessage now takes a []ContentBlock (symmetric with
addAssistantMessage). Introduce a thin addUserText wrapper in agent.zig
for the plain-text case and update every call site in agent.zig and
anthropic_messages_json.zig accordingly.

1 files changed, 53 insertions, 0 deletions

diff --git a/build.zig b/build.zig
index c732d2d..87901c6 100644
--- a/build.zig
+++ b/build.zig
@@ -13,6 +13,18 @@ pub fn build(b: *std.Build) void {
         .optimize = optimize,
     });
 
+    // The native Lua C-module (`libpanto-lua`). We embed its compiled
+    // `panto.so` into the panto binary and stage it onto the embedded
+    // VM's `package.cpath` at bootstrap, so `require('panto')` resolves
+    // to the native agent/stream module on a cold, network-less machine
+    // (the guaranteed initial module load — see
+    // docs/step19-cli-panto-module-plan.md).
+    const panto_lua_dep = b.dependency("panto_lua", .{
+        .target = target,
+        .optimize = optimize,
+    });
+    const panto_so_embed_path = generatePantoSoEmbed(b, panto_lua_dep);
+
     // TOML parser (used by the CLI for ~/.config/panto/models.toml).
     // We disable the upstream's optional thread-pool dep — we only need
     // sequential parsing of a small config file.
@@ -76,6 +88,9 @@ pub fn build(b: *std.Build) void {
     exe_mod.addImport("embedded_agent", b.createModule(.{
         .root_source_file = agent_embed_path,
     }));
+    exe_mod.addImport("embedded_panto_so", b.createModule(.{
+        .root_source_file = panto_so_embed_path,
+    }));
     // Link Lua. We can't use a static library here because the
     // standard archive-linking behavior drops object files whose
     // symbols nothing in our code references — e.g. `lua_settable`,
@@ -136,6 +151,9 @@ pub fn build(b: *std.Build) void {
     test_mod.addImport("embedded_agent", b.createModule(.{
         .root_source_file = agent_embed_path,
     }));
+    test_mod.addImport("embedded_panto_so", b.createModule(.{
+        .root_source_file = panto_so_embed_path,
+    }));
     addLuaSources(test_mod, lua_src, lua_anchor_path);
     test_mod.addIncludePath(lua_src.path("src"));
     test_mod.linkLibrary(lua_repl);
@@ -421,6 +439,41 @@ fn generateLuaHeadersEmbed(
     return out_zig;
 }
 
+/// Codegen step: embed the compiled `libpanto-lua` `panto.so` into a Zig
+/// module the bootstrap stages onto the embedded VM's `package.cpath`.
+///
+/// We address the artifact via `dep.artifact("panto")` (the `addLibrary`
+/// Compile step named `panto` in `libpanto-lua/build.zig`) and embed its
+/// emitted binary by bytes — name-agnostic, so the upstream `libpanto.so`/
+/// `libpanto.dylib` filename is irrelevant; we always stage it as
+/// `panto.so`. The `.so` is copied next to the generated module so
+/// `@embedFile` can resolve it.
+fn generatePantoSoEmbed(
+    b: *std.Build,
+    panto_lua_dep: *std.Build.Dependency,
+) std.Build.LazyPath {
+    const so_path = panto_lua_dep.artifact("panto").getEmittedBin();
+
+    const tool = b.addExecutable(.{
+        .name = "gen-panto-so-embed",
+        .root_module = b.createModule(.{
+            .root_source_file = b.path("build/gen_panto_so_embed.zig"),
+            .target = b.graph.host,
+            .optimize = .Debug,
+        }),
+    });
+
+    const run = b.addRunArtifact(tool);
+    // The generated module `@embedFile`s exactly this name.
+    run.addArg("panto.so");
+    const gen_file = run.addOutputFileArg("embedded_panto_so.zig");
+
+    const wf = b.addWriteFiles();
+    const out_zig = wf.addCopyFile(gen_file, "embedded_panto_so.zig");
+    _ = wf.addCopyFile(so_path, "panto.so");
+    return out_zig;
+}
+
 // Lua 5.4.x core VM + standard library. Excludes lua.c (interpreter entry
 // point) and luac.c (compiler entry point).
 const lua_files = [_][]const u8{