[core] coerce set_interval(0) to 1ms to prevent scheduler spin

Users (notably PollingComponents with update_interval: 0ms) have
historically relied on set_interval(0) as a pseudo-loop() mechanism. A
literal interval=0 causes Scheduler::call() to spin — the item is
always 'due now' after re-scheduling, so the scheduler loop never
returns, starves the main loop, and triggers a WDT reset in the field.

Coerce interval=0 to 1ms at creation so existing code keeps working at
~1kHz instead of spinning, while still emitting the warning pointing
authors at HighFrequencyLoopRequester (the intended mechanism for
running fast in the main loop). Zero-delay timeouts (defer/set_timeout)
remain legitimate one-shots and are unaffected — defer is a one-shot,
not a spin risk.

esphome/core/scheduler.cpp

@@ -144,13 +144,17 @@ void HOT Scheduler::set_timer_common_(Component *component, SchedulerItem::Type
     return;
   }
 
-  // An interval of 0 means "fire every tick forever," which is misuse: it
-  // asks the main loop to spin unbounded. The correct mechanism for running
-  // fast in the main loop is HighFrequencyLoopRequester, not a zero-delay
-  // interval. Zero-delay timeouts (defer) remain legitimate one-shots.
+  // An interval of 0 means "fire every tick forever," which is misuse: the
+  // item would always be due, causing Scheduler::call() to spin and starve
+  // the main loop (WDT reset in the field). Coerce to 1ms so existing code
+  // using update_interval=0ms as a pseudo-loop() continues to work at ~1kHz,
+  // and warn so authors can migrate to HighFrequencyLoopRequester which is
+  // the intended mechanism for running fast in the main loop. Zero-delay
+  // timeouts (defer) remain legitimate one-shots and are not affected.
   if (type == SchedulerItem::INTERVAL && delay == 0) [[unlikely]] {
-    ESP_LOGW(TAG, "[%s] set_interval(0) is misuse — use HighFrequencyLoopRequester",
+    ESP_LOGW(TAG, "[%s] set_interval(0) is misuse — coercing to 1ms. Use HighFrequencyLoopRequester instead.",
              component ? LOG_STR_ARG(component->get_component_log_str()) : LOG_STR_LITERAL("?"));
+    delay = 1;
   }
 
   // Take lock early to protect scheduler_item_pool_ access and retry-cancelled check