fix(desktop): clamp Goal.progress to its documented 0-100 range

[eulicesl]

What

Goal.progress (in desktop/macos/Desktop/Sources/APIClient.swift) is documented as returning a percentage in the range 0-100, but it only guarded against divide-by-zero — it did not clamp the result:

// before
var progress: Double {
  guard targetValue != minValue else { return 0 }
  return ((currentValue - minValue) / (targetValue - minValue)) * 100.0
}

When currentValue is below minValue (e.g. a goal whose baseline is above zero, or a value that regresses below its starting point), this returns a negative percentage. Consumers only clamp the upper bound:

• MainWindow/Components/GoalsWidget.swift:164 → min(goal.progress / 100.0, 1.0)
• MainWindow/Components/GoalsWidget.swift:775 → .trim(from: 0, to: min(goal.progress / 100, 1.0))
• ProactiveAssistants/.../TaskPrioritizationService.swift:185 → "(\(Int(goal.progress))% complete)"

So a negative value passes straight through: Path.trim(from: 0, to: <negative>) renders an empty/inverted arc, and the prompt text reads e.g. "(-40% complete)".

Fix

Clamp at the source so the getter honors its own 0-100 contract:

// after
var progress: Double {
  guard targetValue != minValue else { return 0 }
  let pct = ((currentValue - minValue) / (targetValue - minValue)) * 100.0
  return min(max(pct, 0), 100)
}

For all in-range values the output is identical — only out-of-range inputs change, toward the documented contract. Existing caller-side upper-bound clamps are left in place (harmless/defensive).

Tests

Adds Desktop/Tests/GoalProgressTests.swift (decoder-based, matching the repo's existing test style):

• mid-range → 50
• currentValue < minValue → 0 (the regression)
• currentValue > targetValue → 100
• targetValue == minValue → 0 (divide-by-zero guard)

Verification

• Pure-value clamp; no schema/IO/migration. Revertible in one commit.
• ⚠️ Not compiled/run locally — authored in a Linux container with no Apple SDK. Needs a macOS build (xcrun swift test --package-path Desktop --filter GoalProgressTests) / CI to confirm.

Draft until a macOS build/test pass confirms it green.

🤖 Generated with Claude Code

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