refactor: apply minimal tfcode branding

- Rename packages/opencode → packages/tfcode (directory only)
- Rename bin/opencode → bin/tfcode (CLI binary)
- Rename .opencode → .tfcode (config directory)
- Update package.json name and bin field
- Update config directory path references (.tfcode)
- Keep internal code references as 'opencode' for easy upstream sync
- Keep @opencode-ai/* workspace package names

This minimal branding approach allows clean merges from upstream
opencode repository while providing tfcode branding for users.

packages/tfcode/script/build-node.ts

@@ -0,0 +1,54 @@
+#!/usr/bin/env bun
+
+import fs from "fs"
+import path from "path"
+import { fileURLToPath } from "url"
+
+const __filename = fileURLToPath(import.meta.url)
+const __dirname = path.dirname(__filename)
+const dir = path.resolve(__dirname, "..")
+
+process.chdir(dir)
+
+// Load migrations from migration directories
+const migrationDirs = (
+  await fs.promises.readdir(path.join(dir, "migration"), {
+    withFileTypes: true,
+  })
+)
+  .filter((entry) => entry.isDirectory() && /^\d{4}\d{2}\d{2}\d{2}\d{2}\d{2}/.test(entry.name))
+  .map((entry) => entry.name)
+  .sort()
+
+const migrations = await Promise.all(
+  migrationDirs.map(async (name) => {
+    const file = path.join(dir, "migration", name, "migration.sql")
+    const sql = await Bun.file(file).text()
+    const match = /^(\d{4})(\d{2})(\d{2})(\d{2})(\d{2})(\d{2})/.exec(name)
+    const timestamp = match
+      ? Date.UTC(
+          Number(match[1]),
+          Number(match[2]) - 1,
+          Number(match[3]),
+          Number(match[4]),
+          Number(match[5]),
+          Number(match[6]),
+        )
+      : 0
+    return { sql, timestamp, name }
+  }),
+)
+console.log(`Loaded ${migrations.length} migrations`)
+
+await Bun.build({
+  target: "node",
+  entrypoints: ["./src/node.ts"],
+  outdir: "./dist",
+  format: "esm",
+  external: ["jsonc-parser"],
+  define: {
+    OPENCODE_MIGRATIONS: JSON.stringify(migrations),
+  },
+})
+
+console.log("Build complete")