refactor(brain-install): filter plugins by target ENUM in install-plugins.sh

Closes тех-долг из routing.md v1.1 §4.1 — install-plugins.sh теперь
фильтрует entries по полю `target` относительно режима install'а.

Added флаг `--install-target=user|consumer` (required, с fallback на 'user'
+ warning для backwards-compat прямых вызовов из тестов). Filter jq-выражение:

  user:     target ∈ {"user-level", "user-level+consumer"}
  consumer: target ∈ {"consumer", "user-level+consumer"}

scripts/install.sh теперь передаёт --install-target автоматически на основе
detected $mode (user|project). Regression: текущие 8 entries → 8 plugins при
--install-target=user, 2 plugins (FD + UPM, target=user-level+consumer) при
--install-target=consumer.

Подготовка под Phase 1: добавление 4 consumer-only entries (target=consumer)
и 1 user-level+consumer entry (context7) в plugins-manifest.json — filter
обеспечит, что в brain user-level попадут только нужные.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scripts/install.sh

@@ -144,9 +144,13 @@ elif [ "$mode" = "user" ]; then
     # Plugins
     if [ "$with_plugins" = "yes" ]; then
         if [ -f "$src/marketplaces.json" ] && [ -f "$src/plugins-manifest.json" ]; then
+            # Map mode (user|project) to install-target (user|consumer)
+            plugin_target="user"
+            [ "$mode" = "project" ] && plugin_target="consumer"
             bash "$SCRIPT_DIR/lib/install-plugins.sh" \
                 --marketplaces="$src/marketplaces.json" \
-                --manifest="$src/plugins-manifest.json" || exit 6
+                --manifest="$src/plugins-manifest.json" \
+                --install-target="$plugin_target" || exit 6
         fi
     fi
 fi

scripts/lib/install-plugins.sh

@@ -18,16 +18,30 @@ source "$SCRIPT_DIR/common.sh"
 
 marketplaces=""
 manifest=""
+install_target=""
 
 while [ $# -gt 0 ]; do
     case "$1" in
         --marketplaces=*) marketplaces="${1#--marketplaces=}" ;;
         --manifest=*) manifest="${1#--manifest=}" ;;
+        --install-target=*) install_target="${1#--install-target=}" ;;
         *) log_error "Unknown arg: $1"; exit 1 ;;
     esac
     shift
 done
 
+# Backwards-compat: если флаг не передан, default 'user' с warning
+if [ -z "$install_target" ]; then
+    log_warn "--install-target not specified, defaulting to 'user' (deprecated path)"
+    install_target="user"
+fi
+
+# Validate
+case "$install_target" in
+    user|consumer) ;;
+    *) log_error "--install-target must be 'user' or 'consumer', got: $install_target"; exit 1 ;;
+esac
+
 [ -f "$marketplaces" ] || { log_error "Marketplaces file: $marketplaces not found"; exit 1; }
 [ -f "$manifest" ] || { log_error "Manifest file: $manifest not found"; exit 1; }
 
@@ -57,8 +71,17 @@ for mp in $(jq -r 'keys[]' "$marketplaces"); do
     fi
 done
 
-# Install plugins
-for plugin in $(jq -r '.plugins | keys[]' "$manifest"); do
+# Install plugins (filtered by target ENUM per --install-target)
+case "$install_target" in
+    user)
+        filter='.plugins | to_entries[] | select(.value[0].target == "user-level" or .value[0].target == "user-level+consumer") | .key'
+        ;;
+    consumer)
+        filter='.plugins | to_entries[] | select(.value[0].target == "consumer" or .value[0].target == "user-level+consumer") | .key'
+        ;;
+esac
+
+for plugin in $(jq -r "$filter" "$manifest"); do
     expected_sha=$(jq -r ".plugins[\"$plugin\"][0].gitCommitSha" "$manifest")
     expected_ver=$(jq -r ".plugins[\"$plugin\"][0].version" "$manifest")