make relay post-switching delay a config parameter

[DedeHai]

Can be set in relay configuration, stored in cfg.

Summary by CodeRabbit

• New Features

  • Added a configurable relay activation delay in the LED settings.
  • The relay delay (in milliseconds) can be adjusted via the Relay controls and is persisted in configuration.
  • Settings import/export now include the relay delay value.

• Bug Fixes

  • Relay activation timing now uses the configured relay delay consistently instead of a fixed default value.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

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📥 Commits

Reviewing files that changed from the base of the PR and between cd9ae4b and dadd53c.

📒 Files selected for processing (1)

• wled00/data/settings_leds.htm

🚧 Files skipped from review as they are similar to previous changes (1)

• wled00/data/settings_leds.htm

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Walkthrough

Adds a configurable relay-to-LED stabilization delay, exposes it in LED settings, persists it as relay.del, supports build-time defaults, and uses the configured value during relay activation.

Changes

Configurable relay delay

Layer / File(s)	Summary
Relay delay contract wled00/const.h, wled00/wled.h	Defines an overridable 50 ms default and introduces the relayDelay global initialized from it.
Settings and persistence wled00/data/settings_leds.htm, wled00/xml.cpp, wled00/set.cpp, wled00/cfg.cpp	Adds the RLD form field, parses submitted values, and reads or writes the value as relay.del.
Relay activation timing wled00/button.cpp	Uses relayDelay instead of the fixed RELAY_DELAY during relay activation.

Estimated code review effort: 2 (Simple) | ~10 minutes

Sequence Diagram(s)

sequenceDiagram
  participant settings_leds.htm
  participant getSettingsJS
  participant handleSettingsSet
  participant cfg.cpp
  participant handleOnOff
  participant LEDs

  settings_leds.htm->>getSettingsJS: Display RLD from relayDelay
  settings_leds.htm->>handleSettingsSet: Submit RLD
  handleSettingsSet->>cfg.cpp: Store relayDelay as relay.del
  cfg.cpp-->>settings_leds.htm: Load relay.del into RLD
  handleOnOff->>handleOnOff: Wait relayDelay
  handleOnOff->>LEDs: Send LED data

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Possibly related PRs

• wled/WLED#5315: Both changes modify relay control timing or handling in wled00/button.cpp.
• wled/WLED#5737: Both changes modify settings JavaScript generation in wled00/xml.cpp.

Suggested labels: enhancement

Suggested reviewers: netmindz, softhack007

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: making the relay post-switching delay configurable.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@wled00/data/settings_leds.htm`:
- Line 814: Update the relay-delay assignment in loadCfg() to read the persisted
hw.relay.del configuration key, matching the key written by cfg.json, while
preserving the existing RLD field update behavior.

In `@wled00/set.cpp`:
- Line 311: Clamp or reject relay-delay values to the valid 0..65535 range
before storing them in relayDelay. Update the RLD assignment in
wled00/set.cpp:311 and the relay.del assignment in wled00/cfg.cpp:464,
preserving valid inputs while preventing malformed values from reaching
delay(relayDelay).

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 44eb97e5-6f7d-482d-b53d-a54d3b64c0c1

📥 Commits

Reviewing files that changed from the base of the PR and between e391183 and cd9ae4b.

📒 Files selected for processing (7)

• wled00/button.cpp
• wled00/cfg.cpp
• wled00/const.h
• wled00/data/settings_leds.htm
• wled00/set.cpp
• wled00/wled.h
• wled00/xml.cpp