feat: add access control to channels with various modes

- Introduced AccessMode enum to define channel access levels: Public, PasswordProtected, AccountRequired, and OwnerOnly.
- Updated Channel and ProgrammingBlock entities to include access_mode and access_password_hash fields.
- Enhanced create and update channel functionality to handle access mode and password.
- Implemented access checks in channel routes based on the defined access modes.
- Modified frontend components to support channel creation and editing with access control options.
- Added ChannelPasswordModal for handling password input when accessing restricted channels.
- Updated API calls to include channel and block passwords as needed.
- Created database migrations to add access_mode and access_password_hash columns to channels table.

k-tv-frontend/app/(main)/tv/components/channel-password-modal.tsx

@@ -0,0 +1,61 @@
+"use client";
+
+import { useState } from "react";
+
+interface ChannelPasswordModalProps {
+  label: string;
+  onSubmit: (password: string) => void;
+  onCancel: () => void;
+}
+
+export function ChannelPasswordModal({
+  label,
+  onSubmit,
+  onCancel,
+}: ChannelPasswordModalProps) {
+  const [value, setValue] = useState("");
+
+  const handleSubmit = (e: React.FormEvent) => {
+    e.preventDefault();
+    if (value.trim()) onSubmit(value.trim());
+  };
+
+  return (
+    <div className="absolute inset-0 z-40 flex items-center justify-center bg-black/80 backdrop-blur-sm">
+      <form
+        onSubmit={handleSubmit}
+        className="flex w-80 flex-col gap-4 rounded-xl border border-zinc-700 bg-zinc-900 p-6 shadow-2xl"
+      >
+        <div className="text-center">
+          <p className="text-sm font-semibold uppercase tracking-widest text-zinc-400">
+            {label}
+          </p>
+        </div>
+        <input
+          type="password"
+          autoFocus
+          value={value}
+          onChange={(e) => setValue(e.target.value)}
+          placeholder="Enter password"
+          className="rounded-md border border-zinc-700 bg-zinc-800 px-3 py-2 text-sm text-zinc-100 placeholder:text-zinc-600 focus:border-zinc-500 focus:outline-none"
+        />
+        <div className="flex gap-2">
+          <button
+            type="button"
+            onClick={onCancel}
+            className="flex-1 rounded-md border border-zinc-700 bg-zinc-800/60 px-4 py-2 text-xs text-zinc-400 transition-colors hover:bg-zinc-700 hover:text-zinc-100"
+          >
+            Cancel
+          </button>
+          <button
+            type="submit"
+            disabled={!value.trim()}
+            className="flex-1 rounded-md bg-zinc-100 px-4 py-2 text-xs font-medium text-zinc-900 transition-colors hover:bg-white disabled:opacity-40"
+          >
+            Unlock
+          </button>
+        </div>
+      </form>
+    </div>
+  );
+}