Add guidance to use Throttle for time-based rate limiting in agent instructions

.github/copilot-instructions.md

@@ -197,6 +197,7 @@ firmware/
 - Use `assert()` for invariants that should never fail
 - C++17 features are available (`std::optional`, structured bindings, `if constexpr`, etc.)
 - **Keep code comments minimal — one or two lines, max.** Comment only when the _why_ isn't obvious from the code; never restate what the next line does. No multi-paragraph block comments explaining straightforward changes. The diff and commit message carry the rationale; the code carries the behavior.
+- **Use `Throttle` for time-based rate limiting, not raw `millis()` math.** `src/mesh/Throttle.h` provides `Throttle::isWithinTimespanMs(lastMs, intervalMs)` (returns true while inside the cooldown) and `Throttle::execute(&lastMs, intervalMs, func)` (function-pointer form that updates the timestamp on fire). Use these for any "did N ms pass since X" check — raw `millis() > lastMs + N` is rollover-unsafe (breaks after ~49.7 days) and inconsistent with the rest of the codebase. The helpers compute `now - lastMs` with unsigned subtraction, which wraps correctly.
 
 ### Naming Conventions
 

AGENTS.md

@@ -67,6 +67,7 @@ Key rotation to never trigger casually: only the **full** factory reset (`factor
 - **Run `trunk fmt` before proposing a commit.** The `trunk_check` CI gate will reject unformatted code.
 - **`confirm=True` on destructive MCP tools is a real gate, not a formality.** Don't bypass it via auto-approve settings.
 - **Keep code comments minimal — one or two lines, max.** Comment only when the _why_ isn't obvious from the code; never restate what the next line does. No multi-paragraph block comments explaining straightforward changes. The diff and commit message carry the rationale; the code carries the behavior.
+- **Use `Throttle` for time-based rate limiting, not raw `millis()` math.** `src/mesh/Throttle.h` provides `Throttle::isWithinTimespanMs(lastMs, intervalMs)` (returns true while inside the cooldown) and `Throttle::execute(&lastMs, intervalMs, func)` (function-pointer form that updates the timestamp on fire). Use these for any "did N ms pass since X" check — raw `millis() > lastMs + N` is rollover-unsafe (breaks after ~49.7 days) and inconsistent with the rest of the codebase. The helpers compute `now - lastMs` with unsigned subtraction, which wraps correctly.
 
 ## Typical agent workflows