Add single channel mode feature.

The addition of a single-channel mode implied further modularisation of the component. This commit has broken the component down into the following modules to avoid a huge single source file and to make unit testing easier.

The modules:

- Separation of public and private code
- *types and *defs
- public relay_chn API
- *adapter
- *output
- *run_info
- *core
- *ctl (control)
- *tilt

Closes #957.

src/relay_chn_ctl_single.c

@@ -0,0 +1,76 @@
+/*
+ * SPDX-FileCopyrightText: 2025 Kozmotronik Tech
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include "relay_chn_priv_types.h"
+#include "relay_chn_core.h"
+#include "relay_chn_ctl.h"
+#include "relay_chn_output.h"
+
+
+static relay_chn_ctl_t chn_ctl;
+
+
+esp_err_t relay_chn_ctl_init(relay_chn_output_t *output, relay_chn_run_info_t *run_info)
+{
+    // Initialize the relay channel
+    chn_ctl.id = 0; // Single channel, so ID is 0
+    chn_ctl.state = RELAY_CHN_STATE_IDLE;
+    chn_ctl.pending_cmd = RELAY_CHN_CMD_NONE;
+    chn_ctl.output = output;
+    chn_ctl.run_info = run_info;
+    return relay_chn_init_timer(&chn_ctl); // Create direction change inertia timer
+}
+
+
+void relay_chn_ctl_deinit()
+{
+    if (chn_ctl.inertia_timer != NULL) {
+        esp_timer_delete(chn_ctl.inertia_timer);
+        chn_ctl.inertia_timer = NULL;
+    }
+}
+
+/* relay_chn APIs */
+relay_chn_state_t relay_chn_ctl_get_state()
+{
+    return chn_ctl.state;
+}
+
+char *relay_chn_ctl_get_state_str()
+{
+    return relay_chn_state_str(chn_ctl.state);
+}
+
+void relay_chn_ctl_run_forward()
+{
+    relay_chn_issue_cmd(&chn_ctl, RELAY_CHN_CMD_FORWARD);
+}
+
+void relay_chn_ctl_run_reverse()
+{
+    relay_chn_issue_cmd(&chn_ctl, RELAY_CHN_CMD_REVERSE);
+}
+
+void relay_chn_ctl_stop()
+{
+    relay_chn_issue_cmd(&chn_ctl, RELAY_CHN_CMD_STOP);
+}
+
+void relay_chn_ctl_flip_direction()
+{
+    relay_chn_issue_cmd(&chn_ctl, RELAY_CHN_CMD_FLIP);    
+}
+
+relay_chn_direction_t relay_chn_ctl_get_direction()
+{
+    return relay_chn_output_get_direction(chn_ctl.output);
+}
+/* relay_chn APIs */
+
+relay_chn_ctl_t *relay_chn_ctl_get()
+{
+    return &chn_ctl;
+}