refactor: P0 architecture improvements

- Split browser.ts (700 lines) into src/browser/ module (page, mcp, errors, discover, tabs, index)
- Add unified error handling: CliError base class + logger module
- Enable TypeScript strict mode, fix 12 type errors
- Extract inline build scripts to scripts/clean-yaml.cjs and copy-yaml.cjs
- All 178 unit tests pass, build produces 83 entries across 19 sites

scripts/clean-yaml.cjs

@@ -0,0 +1,19 @@
+/**
+ * Clean YAML files from dist/clis/ before copying fresh ones.
+ */
+const { readdirSync, rmSync, existsSync, statSync } = require('fs');
+const path = require('path');
+
+function walk(dir) {
+  if (!existsSync(dir)) return;
+  for (const f of readdirSync(dir)) {
+    const fp = path.join(dir, f);
+    if (statSync(fp).isDirectory()) {
+      walk(fp);
+    } else if (/\.ya?ml$/.test(f)) {
+      rmSync(fp);
+    }
+  }
+}
+
+walk('dist/clis');

scripts/copy-yaml.cjs

@@ -0,0 +1,21 @@
+/**
+ * Copy YAML files from src/clis/ to dist/clis/.
+ */
+const { readdirSync, copyFileSync, mkdirSync, existsSync, statSync } = require('fs');
+const path = require('path');
+
+function walk(src, dst) {
+  if (!existsSync(src)) return;
+  for (const f of readdirSync(src)) {
+    const sp = path.join(src, f);
+    const dp = path.join(dst, f);
+    if (statSync(sp).isDirectory()) {
+      walk(sp, dp);
+    } else if (/\.ya?ml$/.test(f)) {
+      mkdirSync(path.dirname(dp), { recursive: true });
+      copyFileSync(sp, dp);
+    }
+  }
+}
+
+walk('src/clis', 'dist/clis');