fix(ci): pin ReactESP to ~3.2.0 to unbreak arduino_esp32 build

[dirkwa]

Summary

ReactESP 3.3.0 (Apr 2026) broke the arduino_esp32 CI matrix env. With the existing mairas/ReactESP @ ^3.2.0 constraint, every fresh CI install now pulls 3.3.0 and fails to compile under the Arduino-Espressif toolchain. Pinning to ~3.2.0 restores the matrix.

What 3.3.0 changed

Two upstream changes in event_loop.h:

1. Uses std::set::node_type (a C++17 feature) — but espressif32 @ ^6.9.0 (the platform used by arduino_esp32) defaults to C++14.
2. References std::vector without #include <vector> — an outright bug in 3.3.0.

The pioarduino envs happen to compile fine because their newer toolchain defaults to gnu++2a and transitively pulls <vector>, but the arduino_esp32 matrix entries fail like so:

error: 'node_type' in 'using TimedEventSet = ...' does not name a type
error: 'vector' in namespace 'std' does not name a template type

(see run 26077887618, the failing CI on #960 — that PR's code change is unrelated; it just happens to be the first push since 3.3.0 dropped on Apr 15.)

The change

• platformio.ini: mairas/ReactESP @ ^3.2.0 → ~3.2.0
• library.json: ^3.1.0 → ~3.2.0

~3.2.0 allows future 3.2.x patches but blocks 3.3.x until upstream ships a fix.

Verification

Locally built both envs against the pinned 3.2.0 on a Pi 5 (running the same ci/run-tests.sh script CI uses):

• arduino_esp32 — [PASSED], no event_loop.h errors.
• pioarduino_esp32 — compile passes (no node_type / vector errors); the only local failure is an unrelated min_spiffs.csv link-step issue from my multi-framework install, not present in CI.

[dirkwa]

I am looking now into 3.3.0, maybe we can close this and land that fix PR instead.

[dirkwa]

Note: the real root-cause fix is mairas/ReactESP#40 (adds the missing #include <vector> and gates the C++17 extract/insert(node) hot path on __cplusplus >= 201703L with a C++14 fallback). Once that merges and a 3.3.1 ships, this ~3.2.0 pin can be relaxed back to ^3.2.0 (or bumped to ^3.3.1). This PR remains the right immediate unblock since we can't wait on upstream to merge.

[mairas]

Acknowledging the root cause, sorry about that! I've merged mairas/ReactESP#40 and released v3.3.1. Closing this PR.