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-backend/domain/src/value_objects/scheduling.rs

@@ -1,6 +1,17 @@
 use serde::{Deserialize, Serialize};
 use std::fmt;
 
+/// Controls who can view a channel's broadcast and stream.
+#[derive(Debug, Clone, Default, Serialize, Deserialize, PartialEq, Eq)]
+#[serde(rename_all = "snake_case")]
+pub enum AccessMode {
+    #[default]
+    Public,
+    PasswordProtected,
+    AccountRequired,
+    OwnerOnly,
+}
+
 /// Opaque media item identifier — format is provider-specific internally.
 /// The domain never inspects the string; it just passes it back to the provider.
 #[derive(Debug, Clone, PartialEq, Eq, Hash, Serialize, Deserialize)]