refactor: convert to bun-workspaces monorepo (desktop/ + www/)

- Move the Tauri app (React frontend + Rust backend) into desktop/ via
  git mv — configs unchanged (relative paths: tauri.conf.json, vite.config.ts)
- Root package.json becomes a private bun workspace container with
  orchestration scripts; desktop package renamed gridline-desktop
- Scaffold www/ with Astro 7 + Tailwind v4 (hand-wired vite plugin,
  static output, ready for Dokploy)
- Update release.yml for the new layout: projectPath: desktop,
  desktop/src-tauri resource paths, rust-cache workspace path
- Update README + AGENTS.md structure trees and dev commands
- Verified: vitest (1074), cargo test (354), desktop build, tauri dev
  (window launches), tauri build (dmg + app bundles), Astro build

desktop/src-tauri/src/commands/maintenance.rs

@@ -0,0 +1,39 @@
+use tauri::State;
+use crate::db::pool::{ConnectionPoolManager, DbHandle};
+use crate::models::MaintenanceResult;
+
+/// Run a table-scoped maintenance command via the SIMPLE query protocol
+/// (never inside a transaction — VACUUM cannot run in a transaction block).
+pub(crate) async fn run_maintenance_inner(
+    pm: &tokio::sync::Mutex<ConnectionPoolManager>, connection_id: &str, schema: &str, table: &str, action: &str,
+) -> Result<MaintenanceResult, String> {
+    let mut pm = pm.lock().await;
+    let client = match pm.get(connection_id) {
+        Some(DbHandle::Postgresql(c, _)) => c,
+        Some(_) => return Err("Maintenance is PostgreSQL-only".into()),
+        None => return Err("Connection not found".into()),
+    };
+    crate::db::object_ddl::validate_object_name(&schema)?;
+    crate::db::object_ddl::validate_object_name(&table)?;
+    let verb = match action {
+        "vacuum" => "VACUUM",
+        "analyze" => "ANALYZE",
+        "reindex" => "REINDEX TABLE",
+        _ => return Err(format!("Unknown maintenance action: {action}")),
+    };
+    let sql = format!("{} {}.{}", verb,
+        crate::db::object_ddl::quote_ident(&schema), crate::db::object_ddl::quote_ident(&table));
+    let start = std::time::Instant::now();
+    client.simple_query(&sql).await
+        .map_err(|e| crate::commands::db_viewer::sanitize_error(&format!("{e}")))?;
+    Ok(MaintenanceResult { duration_ms: start.elapsed().as_millis() as i64, message: format!("{} completed on {}.{}", verb, schema, table) })
+}
+
+#[tauri::command]
+pub async fn run_maintenance(connection_id: String, schema: String, table: String, action: String, state: State<'_, crate::AppState>) -> Result<MaintenanceResult, String> {
+    run_maintenance_inner(&state.pool_manager, &connection_id, &schema, &table, &action).await
+}
+
+#[cfg(test)]
+#[path = "maintenance.test.rs"]
+mod maintenance_test;