Build Cobble project structure from the handoff

- Remove the preset document suite (letters, emails, invoices, quotes,
  PDF generation, line items) with its routes, API handlers and tables
- Rebrand to Cobble: site data, Lato, handoff design tokens (light and
  dark) in main.css, brand assets in public/brand, ember stone logo and
  regenerated favicons
- Add bots, bot_messages, bot_tasks and bot_task_steps tables, regenerate
  DB types (BUN_SQLITE_COBBLE_*) and add a sample crew seed (seed:bots)
- Add the chat shell at /admin/bots: rail with pinned coordinator and
  user popover, bottom-anchored conversation with composer, working-on
  panel, and a send-message API scoped to the session user
- Add BotStone and Wordmark components, crew status and relative time
  utils with tests, and update AGENTS.md

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/functions/backend/db/bots/insert-user-message.ts

@@ -0,0 +1,50 @@
+import type {
+    BUN_SQLITE_COBBLE_BOT_MESSAGES,
+    BunSQLiteTables,
+} from "@/db/types/db";
+import BunSQLite from "@moduletrace/bun-sqlite";
+
+type Params = {
+    bot_id: number;
+    text: string;
+};
+
+/**
+ * Appends a user message to a bot's conversation and bumps its activity.
+ * Callers must check the bot belongs to the session user first.
+ */
+export default async function insertUserMessage({
+    bot_id,
+    text,
+}: Params): Promise<BUN_SQLITE_COBBLE_BOT_MESSAGES> {
+    const now = Date.now();
+
+    const res = await BunSQLite.insert<
+        BUN_SQLITE_COBBLE_BOT_MESSAGES,
+        (typeof BunSQLiteTables)[number]
+    >({
+        table: "bot_messages",
+        data: [{ bot_id, author: "user", text, needs_you: 0 }],
+    });
+
+    const id = res.postInsertReturn?.insertId;
+
+    if (!res.success || !id) {
+        throw new Error(`Failed to save message: ${res.msg}`);
+    }
+
+    await BunSQLite.sql({
+        sql: `UPDATE bots SET last_activity_at = ? WHERE id = ?`,
+        values: [now, bot_id],
+    });
+
+    return {
+        id,
+        bot_id,
+        author: "user",
+        text,
+        needs_you: 0,
+        created_at: now,
+        updated_at: now,
+    };
+}