targets: set DESKTOP_TIER per block, keyed on DESKTOP_APPGROUPS_SELECTED

armbian-config's module_desktops treats minimal / mid / full as
three distinct install targets. The build framework hard-requires
an explicit DESKTOP_TIER whenever BUILD_DESKTOP=yes; a missing
value causes 'module_desktops install' to bail at
config-validation time.

generate_targets.py emits 12 'desktop-*' target blocks across the
stable / legacy / edge / nightly flavours. None of them set
DESKTOP_TIER today, so every regenerated targets.yaml will start
failing desktop builds once the build-side migration (armbian/build#9683
— replace config/desktop/ tree with armbian-config module_desktops)
lands.

Map tier from the existing DESKTOP_APPGROUPS_SELECTED value that
each block already carries:

  DESKTOP_APPGROUPS_SELECTED=''            → DESKTOP_TIER='minimal'
    8 blocks: plain DE + display manager, ~500 MB. Matches the
    bare desktop the empty-appgroup target produced before.

  DESKTOP_APPGROUPS_SELECTED='programming' → DESKTOP_TIER='mid'
    4 blocks: DE + browser + everyday user-facing tools (editor,
    calculator, media, archive, torrent), ~1 GB. Roughly what the
    'programming' appgroup pulled in on top of the bare desktop.

Neither maps to 'full' — none of the current generate_targets.py
blocks wanted the full tier (office suite + creative tools, ~2.5 GB).
Future targets can override per block when needed.

Author: igorpecovnik

scripts/generate_targets.py

@@ -902,6 +902,7 @@ def generate_stable_yaml(conf_wip_boards, manual_content=""):
       DESKTOP_ENVIRONMENT: "xfce"
       DESKTOP_ENVIRONMENT_CONFIG_NAME: "config_base"
       DESKTOP_APPGROUPS_SELECTED: "programming"
+      DESKTOP_TIER: "mid"
     items:
       - *stable-current-slow-hdmi
 """
@@ -927,6 +928,7 @@ def generate_stable_yaml(conf_wip_boards, manual_content=""):
       DESKTOP_ENVIRONMENT: "gnome"
       DESKTOP_ENVIRONMENT_CONFIG_NAME: "config_base"
       DESKTOP_APPGROUPS_SELECTED: "programming"
+      DESKTOP_TIER: "mid"
     items:
 """
         if current_fast:
@@ -955,6 +957,7 @@ def generate_stable_yaml(conf_wip_boards, manual_content=""):
       DESKTOP_ENVIRONMENT: "kde-neon"
       DESKTOP_ENVIRONMENT_CONFIG_NAME: "config_base"
       DESKTOP_APPGROUPS_SELECTED: "programming"
+      DESKTOP_TIER: "mid"
     items:
       - *stable-current-fast-hdmi
 """
@@ -980,6 +983,7 @@ def generate_stable_yaml(conf_wip_boards, manual_content=""):
       DESKTOP_ENVIRONMENT: "xfce"
       DESKTOP_ENVIRONMENT_CONFIG_NAME: "config_base"
       DESKTOP_APPGROUPS_SELECTED: "programming"
+      DESKTOP_TIER: "mid"
     items:
       - *stable-legacy-fast-hdmi
 """
@@ -1001,6 +1005,7 @@ def generate_stable_yaml(conf_wip_boards, manual_content=""):
       DESKTOP_ENVIRONMENT: "xfce"
       DESKTOP_ENVIRONMENT_CONFIG_NAME: "config_base"
       DESKTOP_APPGROUPS_SELECTED: ""
+      DESKTOP_TIER: "minimal"
     items:
 """
         if current_riscv64:
@@ -1170,6 +1175,7 @@ def generate_nightly_yaml(conf_wip_boards, manual_content=""):
       DESKTOP_ENVIRONMENT: "gnome"
       DESKTOP_ENVIRONMENT_CONFIG_NAME: "config_base"
       DESKTOP_APPGROUPS_SELECTED: ""
+      DESKTOP_TIER: "minimal"
     items:
       - *nightly-fast-hdmi
 """
@@ -1191,6 +1197,7 @@ def generate_nightly_yaml(conf_wip_boards, manual_content=""):
       DESKTOP_ENVIRONMENT: "xfce"
       DESKTOP_ENVIRONMENT_CONFIG_NAME: "config_base"
       DESKTOP_APPGROUPS_SELECTED: ""
+      DESKTOP_TIER: "minimal"
     items:
       - *nightly-slow-hdmi
 """
@@ -1212,6 +1219,7 @@ def generate_nightly_yaml(conf_wip_boards, manual_content=""):
       DESKTOP_ENVIRONMENT: "xfce"
       DESKTOP_ENVIRONMENT_CONFIG_NAME: "config_base"
       DESKTOP_APPGROUPS_SELECTED: ""
+      DESKTOP_TIER: "minimal"
     items:
       - *nightly-riscv64
 """
@@ -1453,6 +1461,7 @@ def generate_community_yaml(csc_tvb_boards, manual_content=""):
       DESKTOP_ENVIRONMENT: "gnome"
       DESKTOP_ENVIRONMENT_CONFIG_NAME: "config_base"
       DESKTOP_APPGROUPS_SELECTED: ""
+      DESKTOP_TIER: "minimal"
     items:
       - *community-current-fast-hdmi
 """
@@ -1478,6 +1487,7 @@ def generate_community_yaml(csc_tvb_boards, manual_content=""):
       DESKTOP_ENVIRONMENT: "kde-neon"
       DESKTOP_ENVIRONMENT_CONFIG_NAME: "config_base"
       DESKTOP_APPGROUPS_SELECTED: ""
+      DESKTOP_TIER: "minimal"
     items:
       - *community-current-fast-hdmi
 """
@@ -1503,6 +1513,7 @@ def generate_community_yaml(csc_tvb_boards, manual_content=""):
       DESKTOP_ENVIRONMENT: "xfce"
       DESKTOP_ENVIRONMENT_CONFIG_NAME: "config_base"
       DESKTOP_APPGROUPS_SELECTED: ""
+      DESKTOP_TIER: "minimal"
     items:
 """
         if current_slow:
@@ -1529,6 +1540,7 @@ def generate_community_yaml(csc_tvb_boards, manual_content=""):
       DESKTOP_ENVIRONMENT: "xfce"
       DESKTOP_ENVIRONMENT_CONFIG_NAME: "config_base"
       DESKTOP_APPGROUPS_SELECTED: ""
+      DESKTOP_TIER: "minimal"
     items:
 """
         if current_riscv64: