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/Cargo.toml

@@ -0,0 +1,13 @@
+[workspace]
+resolver = "3"
+
+members = ["tapo", "tapo-py"]
+
+[workspace.dependencies]
+anyhow = "1.0"
+chrono = { version = "0.4.34", default-features = false }
+log = "0.4"
+pyo3 = { version = "0.27" }
+serde = { version = "1.0" }
+serde_json = { version = "1.0" }
+tokio = { version = "1.48", default-features = false }