Dedup Garmin data storage, configurable chart colors, taxonomy fixes, sync/progression fixes

- Remove duplicated Garmin fields from storage; decode display-only fields
  (activity name/type, lap duration/HR, structured workout raw JSON) from
  RawJSON at API-response time instead of storing redundant columns
- Add a fully configurable chart color system (pace/HR main-line colors, 4
  effort-kind colors, tint/darken/brighten intensity knobs) under Profile >
  Chart colors
- Rename training types and fix their display order (Easy, Long, 60'/30'
  Threshold, Tempo, Intervals, MAS Test, Race) everywhere they're listed
- Add an Efficiency Factor progression metric; fix Progression chart axes to
  use tight non-zero-based domains, m:ss/km pace formatting, and rounded
  ticks instead of raw floating-point labels
- Expose the raw get_workout_by_id() payload in the raw-data viewer
  alongside activity/lap/detail JSON; enlarge the modal and shrink array
  indentation for readability
- Fix "last sync" reporting a meaningless activity count: record one
  combined sync run per manual "Sync now" and count genuinely new
  activities instead of re-listing whatever Garmin returned for the queried
  window
- Let a Review Queue activity be manually cleared back to Unclassified, and
  make "Reset all" available even while disconnected from Garmin

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

backend/internal/api/progression.go

@@ -43,6 +43,16 @@ func metricValue(metric string, a store.Activity) (float64, bool) {
 			return 0, false
 		}
 		return *a.AnaerobicTrainingEffect, true
+	case "efficiency_factor":
+		// Speed per heartbeat: how much ground each beat covers, on average.
+		// A rising trend at similar effort/HR over time is a classic sign of
+		// improving aerobic fitness, independent of pace/HR shown alone.
+		// Scaled by 1000 (m/s per bpm is otherwise a tiny fraction like
+		// 0.02, hard to read/compare at a glance).
+		if a.AvgSpeedMps == nil || a.AvgHR == nil || *a.AvgHR <= 0 {
+			return 0, false
+		}
+		return (*a.AvgSpeedMps / *a.AvgHR) * 1000, true
 	default:
 		return 0, false
 	}