fix: reliable accent color in all profiles + BackInfo background

- 04 profile: write AccentPalette (REG_BINARY, 8 shades derived from #223B47)
  alongside AccentColor/AccentColorMenu. Without AccentPalette, Win11 ignores
  the custom accent on Start/taskbar and falls back to the default - the cause
  of "colors not applied everywhere". Also mirror the full theme + accent into
  HKU\.DEFAULT (lock/welcome screen, system context) on top of the Default hive
  and current user, so all profiles match. Mode stays Custom (dark system,
  light apps); ColorPrevalence on for Start/taskbar and title bars/borders.
- BackInfo.ini: BackgroundColor 4668194 -> 2243399. BackInfo reads the value as
  0xRRGGBB (RGB), not COLORREF/BGR, so #223B47 = 0x223B47 = 2243399; the BGR
  value rendered with red/blue swapped.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

assets/Backinfo/BackInfo.ini

@@ -56,8 +56,9 @@
 ;;
 
 [General]
-; #223B47 in COLORREF (0x00BBGGRR): R=34 G=59 B=71 = 71*65536 + 59*256 + 34 = 4668194
+; #223B47 read as 0xRRGGBB decimal: BackInfo uses RGB order here (NOT COLORREF/BGR),
-BackgroundColor = 4668194
+; so 0x223B47 = 2243399. The previous BGR value (4668194) rendered with R/B swapped.
+BackgroundColor = 2243399
 ; AutoBackground=0: do NOT read live desktop color - unreliable during deployment
 ; (live session may not yet reflect the registry background color change)
 AutoBackground = 0

scripts/04-default-profile.ps1

@@ -104,8 +104,35 @@ function Set-ProfileReg {
     }
 }
 
-# Accent color #223B47 stored as ABGR DWORD: 0xFF473B22
+# Accent color #223B47 (R=34 G=59 B=71) stored as ABGR DWORD: 0xFF473B22
 $AccentColorABGR = 0xFF473B22
+$AccentR = 0x22; $AccentG = 0x3B; $AccentB = 0x47
+
+# Build the 8-shade AccentPalette that Settings writes under Explorer\Accent.
+# Without it Win11 ignores the custom accent on Start/taskbar and falls back to
+# the default - the root cause of "colors not applied everywhere". Layout:
+# Light3, Light2, Light1, Accent(base, index 3), Dark1..Dark4. Each entry RGBA.
+function Get-AccentPalette {
+    param([int]$R, [int]$G, [int]$B)
+    $tints  = @(0.70, 0.45, 0.20)              # light3 (lightest) -> light1
+    $shades = @(0.25, 0.45, 0.65, 0.85)        # dark1 -> dark4
+    $bytes  = New-Object System.Collections.Generic.List[byte]
+    foreach ($t in $tints) {
+        $bytes.Add([byte][math]::Round($R + (255 - $R) * $t))
+        $bytes.Add([byte][math]::Round($G + (255 - $G) * $t))
+        $bytes.Add([byte][math]::Round($B + (255 - $B) * $t))
+        $bytes.Add(0xFF)
+    }
+    $bytes.Add([byte]$R); $bytes.Add([byte]$G); $bytes.Add([byte]$B); $bytes.Add(0xFF)  # base accent
+    foreach ($s in $shades) {
+        $bytes.Add([byte][math]::Round($R * (1 - $s)))
+        $bytes.Add([byte][math]::Round($G * (1 - $s)))
+        $bytes.Add([byte][math]::Round($B * (1 - $s)))
+        $bytes.Add(0xFF)
+    }
+    return ,([byte[]]$bytes.ToArray())
+}
+$AccentPalette = Get-AccentPalette $AccentR $AccentG $AccentB
 
 # -----------------------------------------------------------------------
 # Load Default profile hive
@@ -331,6 +358,11 @@ $pinList
     Set-ProfileReg -SubKey "Software\Microsoft\Windows\CurrentVersion\Explorer\Accent" `
                    -Name "StartColorMenu" -Value $AccentColorABGR -Type "DWord"
 
+    # AccentPalette - required for Win11 to actually honor the accent on Start
+    # and taskbar (without it the custom color is dropped for the default).
+    Set-ProfileReg -SubKey "Software\Microsoft\Windows\CurrentVersion\Explorer\Accent" `
+                   -Name "AccentPalette" -Value $AccentPalette -Type "Binary"
+
     # Wallpaper - solid color #223B47 (BackInfo overwrites on logon)
     Set-ProfileReg -SubKey "Control Panel\Colors" `
                    -Name "Background" -Value "34 59 71" -Type "String"
@@ -341,6 +373,34 @@ $pinList
     Set-ProfileReg -SubKey "Control Panel\Desktop" `
                    -Name "TileWallpaper" -Value "0" -Type "String"
 
+    # Mirror the theme + accent into HKU\.DEFAULT so the lock/welcome screen and
+    # system-context UI use the same branding (covers "all profiles", not just
+    # newly created users which inherit from the Default hive above).
+    $defaultColors = @(
+        @{ Key="Software\Microsoft\Windows\CurrentVersion\Themes\Personalize"; Name="SystemUsesLightTheme"; Val=0;                Type="DWord"  },
+        @{ Key="Software\Microsoft\Windows\CurrentVersion\Themes\Personalize"; Name="AppsUseLightTheme";    Val=1;                Type="DWord"  },
+        @{ Key="Software\Microsoft\Windows\CurrentVersion\Themes\Personalize"; Name="ColorPrevalence";      Val=1;                Type="DWord"  },
+        @{ Key="Software\Microsoft\Windows\CurrentVersion\Themes\Personalize"; Name="EnableTransparency";   Val=0;                Type="DWord"  },
+        @{ Key="Software\Microsoft\Windows\DWM";                               Name="AccentColor";          Val=$AccentColorABGR; Type="DWord"  },
+        @{ Key="Software\Microsoft\Windows\DWM";                               Name="ColorizationColor";    Val=$AccentColorABGR; Type="DWord"  },
+        @{ Key="Software\Microsoft\Windows\DWM";                               Name="ColorizationAfterglow";Val=$AccentColorABGR; Type="DWord"  },
+        @{ Key="Software\Microsoft\Windows\DWM";                               Name="ColorPrevalence";      Val=1;                Type="DWord"  },
+        @{ Key="Software\Microsoft\Windows\CurrentVersion\Explorer\Accent";    Name="AccentColorMenu";      Val=$AccentColorABGR; Type="DWord"  },
+        @{ Key="Software\Microsoft\Windows\CurrentVersion\Explorer\Accent";    Name="StartColorMenu";       Val=$AccentColorABGR; Type="DWord"  },
+        @{ Key="Software\Microsoft\Windows\CurrentVersion\Explorer\Accent";    Name="AccentPalette";        Val=$AccentPalette;   Type="Binary" }
+    )
+    foreach ($c in $defaultColors) {
+        $cp = "Registry::HKU\.DEFAULT\$($c.Key)"
+        try {
+            if (-not (Test-Path $cp)) { New-Item -Path $cp -Force -ErrorAction Stop | Out-Null }
+            Set-ItemProperty -Path $cp -Name $c.Name -Value $c.Val -Type $c.Type -Force -ErrorAction Stop
+        }
+        catch {
+            Write-Log "  .DEFAULT color $($c.Key)\$($c.Name) failed - $_" -Level WARN
+        }
+    }
+    Write-Log "  Theme/accent mirrored to HKU\.DEFAULT" -Level OK
+
     # ===================================================================
     # KEYBOARD LAYOUTS - Czech primary, US secondary
     # ===================================================================