hour_effect_v2: add configurable MQTT-driven 3D printer effect

[KrX3D]

Motivation

• Provide a nicer, configurable replacement for the existing hard-coded 3D printer finished blink so an MQTT JSON payload can set colors, effect, speed, intensity, palette and duration.
• Keep backward compatibility with the current /3dPrinterFinshed + true behavior while allowing richer control from a new topic.

Description

• Added a new helper parse3DPrinterEffectPayload(...) to parse JSON payloads and extract r/g/b/w, effect/mode, speed, intensity, palette, and durationMs/duration with clamping and optional active/trigger/state handling.
• Subscribed to a new group topic 3dPrinterEffect in onMqttConnect and extended message handling in onMqttMessage to accept either the legacy /3dPrinterFinshed or the new /3dPrinterEffect topic.
• Updated the 3D-printer MQTT branch to use parsed parameters (or fall back to legacy behavior), apply the requested effect via applyEffectSettings(...), and use a per-trigger activeResetDelayMs value (bounded) for reset timing.
• Added logging for parsing and scheduling, and ensured blocking/debounce behavior is preserved when effects run.

Testing

• Inspected and validated code locations with searches (rg) and file excerpts to ensure hooks were placed in onMqttConnect, onMqttMessage, and reset logic, and verified the new parse3DPrinterEffectPayload declaration and implementation.
• Reviewed change summary with git diff --stat to confirm the intended modifications to usermods/hour_effect_v2/hour_effect_v2.cpp and .h.
• Ran git diff --check which initially reported trailing-whitespace warnings that were addressed before committing, and then committed the changes successfully.
• No full build or hardware integration test was run in this change set; runtime behavior should be validated on device with actual MQTT messages (example JSON payload provided in code/PR metadata).

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Codex Task