Fix repeater echo correlation by removing trailing whitespace in buildPayload()

[Copilot]

Repeater echo tracking was failing because buildPayload() added trailing whitespace when no power setting was specified, causing includes() comparison to fail against echoed messages.

Problem
When messages are echoed through repeaters, Meshtastic adds the sender's device name as a prefix:

• Sent: "@[MapperBot] 45.26900, -75.77755"
• Echoed: "MrAlders0n: @[MapperBot] 45.26900, -75.77755"

The correlation logic uses decryptedMessage.includes(originalPayload) to match echoes, but failed because buildPayload() created payloads with trailing space:

// Before: adds trailing space when suffix is empty
return `${PING_PREFIX} ${coordsStr} ${suffix}`;  // "@[MapperBot] 45.26900, -75.77755 "

Changes

• Modified buildPayload() to trim trailing whitespace:

// After: removes trailing whitespace
return `${PING_PREFIX} ${coordsStr}${suffix}`.trim();  // "@[MapperBot] 45.26900, -75.77755"

This ensures the payload comparison correctly matches echoed messages that contain the payload after the sender prefix.

Original prompt

Problem

The repeater echo tracking message correlation is failing because when messages are echoed back through repeaters, they include the sender's device name as a prefix.

Console Log Evidence

[DEBUG] [MESSAGE_CORRELATION] Decrypted: "MrAlders0n: @[MapperBot] 45.26900, -75.77755" (44 chars)
[DEBUG] [MESSAGE_CORRELATION] Expected:  "@[MapperBot] 45.26900, -75.77755 " (33 chars)
[DEBUG] [MESSAGE_CORRELATION] ❌ REJECT: Message content mismatch (not an echo of our ping)
[DEBUG] [MESSAGE_CORRELATION] This is a different message on the same channel

Root Cause

Two issues are causing the mismatch:

1. Sender name prefix: The decrypted message includes "MrAlders0n: " before the actual payload, but the comparison doesn't account for this properly.

2. Trailing whitespace: The buildPayload() function at line 893-898 creates a payload with a trailing space when no power setting is specified:

   function buildPayload(lat, lon) {
     const coordsStr = `${lat.toFixed(5)}, ${lon.toFixed(5)}`;
     const power = getCurrentPowerSetting();
     const suffix = power ? ` [${power}]` : "";
     return `${PING_PREFIX} ${coordsStr} ${suffix}`;  // Trailing space when suffix is empty!
   }

Solution

Fix the buildPayload() function in content/wardrive.js to trim trailing whitespace:

function buildPayload(lat, lon) {
  const coordsStr = `${lat.toFixed(5)}, ${lon.toFixed(5)}`;
  const power = getCurrentPowerSetting();
  const suffix = power ? ` [${power}]` : "";
  return `${PING_PREFIX} ${coordsStr}${suffix}`.trim();
}

This ensures the expected payload doesn't have trailing whitespace, which will allow the existing decryptedMessage.includes(originalPayload) check at line 1253 to correctly match the echoed message (which contains the payload after the sender prefix).

This pull request was created from Copilot chat.

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