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/workflows/rs-security-audit.yml

@@ -0,0 +1,26 @@
+name: Security
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - "**/Cargo.toml"
+      - "**/Cargo.lock"
+  pull_request:
+    branches:
+      - main
+    paths:
+      - "**/Cargo.toml"
+      - "**/Cargo.lock"
+  schedule:
+    - cron: "0 0 * * *"
+jobs:
+  security_audit:
+    name: Audit
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+      - uses: dtolnay/rust-toolchain@stable
+      - uses: actions-rs/audit-check@v1
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}