feat: per-template metadata — eliminate meta.json merge conflicts

- move each template's metadata to blueprints/<id>/meta.json (442 files, byte-identical roundtrip with the old root meta.json)
- generate the served meta.json at build time into app/public/meta.json (gitignored); pnpm dev/build run the generator first
- CI validates every blueprints/<id>/meta.json via generate-meta.js --check (required fields, id/folder match, logo exists, folder<->meta bidirectionality) and rejects any committed root meta.json
- remove root meta.json, dedupe-and-sort-meta.js and build-scripts/process-meta.js (obsolete)
- update CONTRIBUTING.md, AGENTS.md and README.md

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

.github/workflows/validate.yml

@@ -49,133 +49,10 @@ jobs:
             echo "✅ Blueprint folders validated successfully."
           fi
 
-      - name: Validate meta.json structure and required fields
-        run: |
-          echo "🔍 Validating meta.json structure and required fields..."
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: "20"
 
-          # First check if meta.json exists and is valid JSON
-          if [ ! -f "meta.json" ]; then
-            echo "❌ meta.json file not found"
-            exit 1
-          fi
-
-          if ! jq empty meta.json 2>/dev/null; then
-            echo "❌ meta.json is not a valid JSON file"
-            exit 1
-          fi
-
-          ERROR=0
-          ERRORS_FOUND=""
-
-          # Debug: Show total number of entries
-          TOTAL_ENTRIES=$(jq '. | length' meta.json)
-          echo "📊 Total entries in meta.json: $TOTAL_ENTRIES"
-
-          # Get all entries at once and process them
-          TOTAL_INDEX=$(($TOTAL_ENTRIES - 1))
-          
-          for i in $(seq 0 $TOTAL_INDEX); do
-            entry=$(jq -c ".[$i]" meta.json)
-            INDEX=$((i + 1))
-            
-            echo "-------------------------------------------"
-            echo "🔍 Checking entry #$INDEX..."
-            
-            # Get the ID for better error reporting
-            ID=$(echo "$entry" | jq -r '.id // "UNKNOWN"')
-            echo "📝 Processing entry with ID: $ID"
-            
-            # Validate required top-level fields
-            for field in "id" "name" "version" "description" "logo" "links" "tags"; do
-              if [ "$(echo "$entry" | jq "has(\"$field\")")" != "true" ]; then
-                ERROR_MSG="❌ Entry #$INDEX (ID: $ID) is missing required field: $field"
-                echo "$ERROR_MSG"
-                ERRORS_FOUND="${ERRORS_FOUND}${ERROR_MSG}\n"
-                ERROR=1
-              fi
-            done
-
-            # Validate links object required fields
-            if [ "$(echo "$entry" | jq 'has("links")')" == "true" ]; then
-              for link_field in "github" "website" "docs"; do
-                if [ "$(echo "$entry" | jq ".links | has(\"$link_field\")")" != "true" ]; then
-                  ERROR_MSG="❌ Entry #$INDEX (ID: $ID): links object is missing required field: $link_field"
-                  echo "$ERROR_MSG"
-                  ERRORS_FOUND="${ERRORS_FOUND}${ERROR_MSG}\n"
-                  ERROR=1
-                fi
-              done
-            fi
-
-            # Validate tags array is not empty
-            if [ "$(echo "$entry" | jq '.tags | length')" -eq 0 ]; then
-              ERROR_MSG="❌ Entry #$INDEX (ID: $ID): tags array cannot be empty"
-              echo "$ERROR_MSG"
-              ERRORS_FOUND="${ERRORS_FOUND}${ERROR_MSG}\n"
-              ERROR=1
-            fi
-          done
-
-          echo "-------------------------------------------"
-          if [ $ERROR -eq 1 ]; then
-            echo "❌ meta.json structure validation failed."
-            echo -e "Summary of all errors found:${ERRORS_FOUND}"
-            exit 1
-          else
-            echo "✅ meta.json structure validated successfully."
-          fi
-
-      - name: Validate meta.json matches blueprint folders and logo files
-        run: |
-          echo "🔍 Validating meta.json against blueprint folders and logos..."
-
-          ERROR=0
-
-          # Read all blueprint folder names into an array
-          FOLDERS=($(ls -1 blueprints))
-
-          # Extract ids and logos from meta.json
-          IDS_AND_LOGOS=$(jq -c '.[] | {id, logo}' meta.json)
-
-          # Validate each id in meta.json exists as a folder
-          for item in $IDS_AND_LOGOS; do
-            ID=$(echo "$item" | jq -r '.id')
-            LOGO=$(echo "$item" | jq -r '.logo')
-
-            # Check if folder exists
-            if [ ! -d "blueprints/$ID" ]; then
-              echo "❌ meta.json id \"$ID\" does not have a matching folder in blueprints/"
-              ERROR=1
-              continue
-            fi
-
-            # Check if logo file exists inside its folder
-            if [ ! -f "blueprints/$ID/$LOGO" ]; then
-              echo "❌ Logo \"$LOGO\" defined for \"$ID\" does not exist in blueprints/$ID/"
-              ERROR=1
-            fi
-          done
-
-          # Validate each folder has a matching id in meta.json
-          META_IDS=$(jq -r '.[].id' meta.json)
-          for FOLDER in "${FOLDERS[@]}"; do
-            FOUND=0
-            for ID in $META_IDS; do
-              if [ "$FOLDER" == "$ID" ]; then
-                FOUND=1
-                break
-              fi
-            done
-
-            if [ "$FOUND" -eq 0 ]; then
-              echo "❌ Folder \"$FOLDER\" has no matching id in meta.json"
-              ERROR=1
-            fi
-          done
-
-          if [ $ERROR -eq 1 ]; then
-            echo "❌ meta.json validation failed."
-            exit 1
-          else
-            echo "✅ meta.json validated successfully."
-          fi
+      - name: Validate per-template metadata (blueprints/<id>/meta.json)
+        run: node build-scripts/generate-meta.js --check