feat: enhance Appwrite integration and chat functionality

- Added support for encrypted coach chats with a new `coach_chats` collection in the Appwrite database.
- Updated `.env.example` to include `OLLAMA_API_KEY`, `OLLAMA_MODEL`, and `APPWRITE_API_KEY` for server-side configurations.
- Introduced a setup script in `package.json` for initializing Appwrite database tables.
- Enhanced the Vite configuration to proxy requests to the Ollama API.
- Updated the main application structure to accommodate new chat features and improved theme management.
- Refined CSS styles for better UI consistency and added new components for chat functionality.

api/ollama-chat.js

@@ -0,0 +1,77 @@
+/* global Buffer, fetch, process */
+
+const DEFAULT_MODEL = "deepseek-v4-pro:cloud";
+
+export default async function handler(req, res) {
+  res.setHeader("Access-Control-Allow-Origin", "*");
+  res.setHeader("Access-Control-Allow-Methods", "POST, OPTIONS");
+  res.setHeader("Access-Control-Allow-Headers", "Content-Type, Authorization");
+
+  if (req.method === "OPTIONS") {
+    res.statusCode = 204;
+    res.end();
+    return;
+  }
+
+  if (req.method !== "POST") {
+    res.statusCode = 405;
+    res.end("Method not allowed");
+    return;
+  }
+
+  const apiKey = process.env.OLLAMA_API_KEY;
+  if (!apiKey) {
+    res.statusCode = 500;
+    res.end("OLLAMA_API_KEY is not configured on the server.");
+    return;
+  }
+
+  try {
+    const payload = await readJson(req);
+    const upstream = await fetch("https://ollama.com/api/chat", {
+      method: "POST",
+      headers: {
+        Authorization: `Bearer ${apiKey}`,
+        "Content-Type": "application/json",
+      },
+      body: JSON.stringify({
+        ...payload,
+        model: payload.model || process.env.OLLAMA_MODEL || DEFAULT_MODEL,
+        stream: payload.stream !== false,
+      }),
+    });
+
+    res.statusCode = upstream.status;
+    res.setHeader("Content-Type", upstream.headers.get("content-type") || "application/x-ndjson");
+
+    if (!upstream.ok) {
+      res.end(await upstream.text());
+      return;
+    }
+
+    if (!upstream.body) {
+      res.end();
+      return;
+    }
+
+    const reader = upstream.body.getReader();
+    while (true) {
+      const { done, value } = await reader.read();
+      if (done) break;
+      res.write(Buffer.from(value));
+    }
+    res.end();
+  } catch (error) {
+    res.statusCode = 500;
+    res.end(error instanceof Error ? error.message : "Ollama proxy failed.");
+  }
+}
+
+async function readJson(req) {
+  if (req.body && typeof req.body === "object") return req.body;
+  if (typeof req.body === "string") return JSON.parse(req.body || "{}");
+
+  let raw = "";
+  for await (const chunk of req) raw += chunk;
+  return raw ? JSON.parse(raw) : {};
+}