feat(tapo-agent): add schedule/countdown timer API support

- Fork tapo crate to add missing schedule/timer APIs
- Add get_countdown_rules, get_schedule_rules, get_next_event methods
- New readings: countdown_active, countdown_remain, schedule_count,
  schedule_active_count, next_event_time
- Add local compilation to build script alongside cross-compilation
- Implement offline polling - device collection continues when server disconnects
- Add more device readings: on_time, signal_level, rssi, runtime_today/month, energy_month

Vendored tapo fork in tapo-fork/ with minimal changes to add schedule APIs.

agents/tapo/tapo-fork/.github/dependabot.yml

@@ -0,0 +1,29 @@
+# Please see the documentation for all configuration options:
+# https://docs.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
+
+version: 2
+updates:
+  - package-ecosystem: "cargo"
+    directory: "/"
+    schedule:
+      interval: "daily"
+    commit-message:
+      prefix: "chore"
+      prefix-development: "chore"
+      include: "scope"
+  - package-ecosystem: pip
+    directory: "/tapo-py"
+    schedule:
+      interval: "daily"
+    commit-message:
+      prefix: "chore"
+      prefix-development: "chore"
+      include: "scope"
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"
+    commit-message:
+      prefix: "chore"
+      prefix-development: "chore"
+      include: "scope"