ported everything to Reticulum mesh

Replace HTTP server with Reticulum-native architecture. The server
now speaks only Reticulum, with a client-side gateway providing
browser access by translating HTTP to/from RNS requests.

- Extract db layer (db.py), templates (templates.py), handlers (handlers.py)
- app.py is now the RNS server with persistent identity and destination
- gateway.py bridges HTTP on localhost:8080 to RNS link requests
- Add rns dependency, add .gitignore

db.py

@@ -0,0 +1,149 @@
+import sqlite3
+import requests
+from urllib.parse import urlparse, urljoin
+from bs4 import BeautifulSoup
+
+DATABASE = "index.db"
+
+SKIP_EXT = (".png", ".jpg", ".jpeg", ".gif", ".svg", ".pdf", ".zip", ".mp3", ".mp4", ".css", ".js", ".ico", ".xml", ".json")
+
+
+def get_db():
+    db = sqlite3.connect(DATABASE)
+    db.row_factory = sqlite3.Row
+    return db
+
+
+def init_db():
+    db = sqlite3.connect(DATABASE)
+    db.execute(
+        "CREATE TABLE IF NOT EXISTS pages ("
+        "  id INTEGER PRIMARY KEY AUTOINCREMENT,"
+        "  url TEXT UNIQUE NOT NULL,"
+        "  title TEXT,"
+        "  body TEXT,"
+        "  note TEXT DEFAULT ''"
+        ")"
+    )
+    db.execute(
+        "CREATE VIRTUAL TABLE IF NOT EXISTS pages_fts "
+        "USING fts5(title, body, url, note, content=pages, content_rowid=id)"
+    )
+    db.execute(
+        "CREATE TABLE IF NOT EXISTS links ("
+        "  id INTEGER PRIMARY KEY AUTOINCREMENT,"
+        "  page_id INTEGER NOT NULL,"
+        "  url TEXT NOT NULL,"
+        "  label TEXT,"
+        "  FOREIGN KEY (page_id) REFERENCES pages(id) ON DELETE CASCADE"
+        ")"
+    )
+    db.execute(
+        "CREATE TABLE IF NOT EXISTS settings ("
+        "  key TEXT PRIMARY KEY,"
+        "  value TEXT"
+        ")"
+    )
+    db.execute(
+        "CREATE TABLE IF NOT EXISTS subscriptions ("
+        "  id INTEGER PRIMARY KEY AUTOINCREMENT,"
+        "  url TEXT UNIQUE NOT NULL,"
+        "  name TEXT DEFAULT '',"
+        "  auto_sync INTEGER DEFAULT 0,"
+        "  last_sync TEXT DEFAULT ''"
+        ")"
+    )
+    db.executescript("""
+        CREATE TRIGGER IF NOT EXISTS pages_ai AFTER INSERT ON pages BEGIN
+            INSERT INTO pages_fts(rowid, title, body, url, note)
+            VALUES (new.id, new.title, new.body, new.url, new.note);
+        END;
+        CREATE TRIGGER IF NOT EXISTS pages_ad AFTER DELETE ON pages BEGIN
+            INSERT INTO pages_fts(pages_fts, rowid, title, body, url, note)
+            VALUES ('delete', old.id, old.title, old.body, old.url, old.note);
+        END;
+        CREATE TRIGGER IF NOT EXISTS pages_au AFTER UPDATE ON pages BEGIN
+            INSERT INTO pages_fts(pages_fts, rowid, title, body, url, note)
+            VALUES ('delete', old.id, old.title, old.body, old.url, old.note);
+            INSERT INTO pages_fts(rowid, title, body, url, note)
+            VALUES (new.id, new.title, new.body, new.url, new.note);
+        END;
+    """)
+    db.commit()
+    db.close()
+
+
+def get_setting(key, default=""):
+    db = get_db()
+    row = db.execute("SELECT value FROM settings WHERE key = ?", (key,)).fetchone()
+    db.close()
+    return row["value"] if row else default
+
+
+def set_setting(key, value):
+    db = get_db()
+    db.execute(
+        "INSERT INTO settings (key, value) VALUES (?, ?) "
+        "ON CONFLICT(key) DO UPDATE SET value=excluded.value",
+        (key, value),
+    )
+    db.commit()
+    db.close()
+
+
+def get_site_name():
+    return get_setting("site_name", "tinyweb")
+
+
+def fetch_page(url):
+    resp = requests.get(url, timeout=10, headers={"User-Agent": "TinyWeb/1.0"}, verify=False)
+    resp.raise_for_status()
+    soup = BeautifulSoup(resp.text, "html.parser")
+
+    # extract links before stripping tags
+    domain = urlparse(url).netloc
+    seen = set()
+    links = []
+    for a in soup.find_all("a", href=True):
+        href = urljoin(url, a["href"]).split("#")[0]
+        parsed = urlparse(href)
+        if parsed.netloc != domain:
+            continue
+        if any(href.lower().endswith(ext) for ext in SKIP_EXT):
+            continue
+        if parsed.query or "action=" in href:
+            continue
+        path = parsed.path.lower()
+        if any(s in path for s in ("/special:", "/talk:", "/user:", "/wikipedia:", "/help:", "/portal:", "/file:", "/category:")):
+            continue
+        if href in seen or href == url:
+            continue
+        seen.add(href)
+        label = a.get_text(strip=True) or href
+        links.append((href, label[:200]))
+
+    for tag in soup(["script", "style", "nav", "footer", "header"]):
+        tag.decompose()
+    title = soup.title.string.strip() if soup.title and soup.title.string else url
+    body = soup.get_text(separator=" ", strip=True)
+    return title, body, links
+
+
+def index_url(url, note=""):
+    title, body, links = fetch_page(url)
+    db = get_db()
+    cur = db.execute(
+        "INSERT INTO pages (url, title, body, note) VALUES (?, ?, ?, ?) "
+        "ON CONFLICT(url) DO UPDATE SET title=excluded.title, body=excluded.body, note=excluded.note",
+        (url, title, body, note),
+    )
+    page_id = cur.lastrowid
+    db.execute("DELETE FROM links WHERE page_id = ?", (page_id,))
+    for href, label in links:
+        db.execute(
+            "INSERT INTO links (page_id, url, label) VALUES (?, ?, ?)",
+            (page_id, href, label),
+        )
+    db.commit()
+    db.close()
+    return title