feat(phase-bc): TOML plugin manifests + Solid vitest preset

Plugin TOML support (-tags wazero):
- manifest_toml.go: tryLoadPluginTOML using BurntSushi/toml v1.6.0
- manifest_nottoml.go: no-op stub for default build
- loader.go: prefers plugin.toml, falls back to plugin.json

Solid vitest preset:
- vitest.config.ts: add vite-plugin-solid, expand include to
  src/components/solid/**/*.test.tsx — Badge.test.tsx now runs
  automatically as part of npm test (112 files / 3188 tests)

Server/plugin/loader.go

@@ -49,17 +49,27 @@ func scanPluginDirectory(dir string) ([]foundPlugin, error) {
 			continue
 		}
 		pluginDir := filepath.Join(dir, e.Name())
-		manifestPath := filepath.Join(pluginDir, "plugin.json")
-		raw, rdErr := os.ReadFile(manifestPath)
-		if rdErr != nil {
-			if os.IsNotExist(rdErr) {
-				continue
-			}
-			return nil, fmt.Errorf("plugin %q: read plugin.json: %w", e.Name(), rdErr)
+
+		// Prefer plugin.toml (wazero build) over plugin.json.
+		manifest, ok, tomlErr := tryLoadPluginTOML(pluginDir)
+		if tomlErr != nil {
+			return nil, fmt.Errorf("plugin %q: %w", e.Name(), tomlErr)
 		}
-		manifest, parseErr := ParseManifest(raw)
-		if parseErr != nil {
-			return nil, fmt.Errorf("plugin %q: %w", e.Name(), parseErr)
+		if !ok {
+			// Fall back to plugin.json.
+			manifestPath := filepath.Join(pluginDir, "plugin.json")
+			raw, rdErr := os.ReadFile(manifestPath)
+			if rdErr != nil {
+				if os.IsNotExist(rdErr) {
+					continue
+				}
+				return nil, fmt.Errorf("plugin %q: read plugin.json: %w", e.Name(), rdErr)
+			}
+			var parseErr error
+			manifest, parseErr = ParseManifest(raw)
+			if parseErr != nil {
+				return nil, fmt.Errorf("plugin %q: %w", e.Name(), parseErr)
+			}
 		}
 		// Reject any symlinks anywhere in the plugin directory tree. The asset
 		// handler enforces that resolved paths stay rooted at pluginDir, but

Server/plugin/manifest_nottoml.go

@@ -0,0 +1,10 @@
+//go:build !wazero
+
+// Default build stub — TOML manifest parsing is not compiled in without -tags wazero.
+package plugin
+
+// tryLoadPluginTOML always reports "not present" in the default build so the
+// loader unconditionally falls through to plugin.json.
+func tryLoadPluginTOML(_ string) (*Manifest, bool, error) {
+	return nil, false, nil
+}

Server/plugin/manifest_toml.go

@@ -0,0 +1,39 @@
+//go:build wazero
+
+// TOML manifest support — compiled only with -tags wazero.
+// Plugins may ship either plugin.json or plugin.toml; this file provides
+// tryLoadPluginTOML which the loader calls before falling back to JSON.
+package plugin
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/BurntSushi/toml"
+)
+
+// tryLoadPluginTOML attempts to parse a plugin.toml from pluginDir.
+// Returns the parsed Manifest and true on success.
+// Returns nil, false if no plugin.toml exists (caller should try plugin.json).
+// Returns nil, false plus logs if plugin.toml exists but is malformed — the
+// caller will skip the plugin and log the error.
+func tryLoadPluginTOML(pluginDir string) (*Manifest, bool, error) {
+	tomlPath := filepath.Join(pluginDir, "plugin.toml")
+	raw, err := os.ReadFile(tomlPath)
+	if os.IsNotExist(err) {
+		return nil, false, nil // not present; try JSON
+	}
+	if err != nil {
+		return nil, false, fmt.Errorf("read plugin.toml: %w", err)
+	}
+
+	var m Manifest
+	if _, err := toml.Decode(string(raw), &m); err != nil {
+		return nil, false, fmt.Errorf("parse plugin.toml: %w", err)
+	}
+	if err := m.Validate(); err != nil {
+		return nil, false, fmt.Errorf("invalid plugin.toml: %w", err)
+	}
+	return &m, true, nil
+}