Use inline :exclude in josh-proxy URL instead of stored filter files

The :+ stored filter syntax doesn't work in josh-proxy URLs.
Inline :exclude[::p1,::p2] works directly — no files to generate
or commit, no extra dependencies.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

bin/josh-sync

@@ -422,28 +422,6 @@ cmd_preflight() {
     warn ".gitea/workflows/josh-sync-reverse.yml not found (optional)"
   fi
 
-  # 4. Exclude filter files
-  local has_excludes
-  has_excludes=$(echo "$JOSH_SYNC_TARGETS" | jq '[.[] | select((.exclude // []) | length > 0)] | length')
-
-  if [ "$has_excludes" -gt 0 ]; then
-    echo ""
-    echo "4. Exclude filter files"
-
-    while IFS= read -r target_name; do
-      local filter_file=".josh-filter-${target_name}.josh"
-      if [ -f "$filter_file" ]; then
-        if git ls-files --error-unmatch "$filter_file" >/dev/null 2>&1; then
-          pass "${filter_file} exists and is tracked"
-        else
-          warn "${filter_file} exists but is NOT committed — run: git add ${filter_file}"
-        fi
-      else
-        fail "${filter_file} not generated — check parse_config"
-      fi
-    done < <(echo "$JOSH_SYNC_TARGETS" | jq -r '.[] | select((.exclude // []) | length > 0) | .name')
-  fi
-
   # Summary
   echo ""
   echo "============================="