feat: add Cursor IDE support with pre-translated configs

Add complete .cursor/ directory with rules, agents, skills, commands,
and MCP config adapted for Cursor's format. This makes ecc-universal
a truly cross-IDE package supporting Claude Code, Cursor, and OpenCode.

- 27 rule files with YAML frontmatter (description, globs, alwaysApply)
- 13 agent files with full model IDs and readonly flags
- 30 skill directories (identical Agent Skills standard, no translation)
- 31 command files (5 multi-* stubbed for missing codeagent-wrapper)
- MCP config with Cursor env interpolation syntax
- README.md and MIGRATION.md documentation
- install.sh --target cursor flag for project-scoped installation
- package.json updated with .cursor/ in files and cursor keywords

install.sh

@@ -2,13 +2,19 @@
 # install.sh — Install claude rules while preserving directory structure.
 #
 # Usage:
-#   ./install.sh <language> [<language> ...]
+#   ./install.sh [--target <claude|cursor>] <language> [<language> ...]
 #
 # Examples:
 #   ./install.sh typescript
 #   ./install.sh typescript python golang
+#   ./install.sh --target cursor typescript
+#   ./install.sh --target cursor typescript python golang
 #
-# This script copies rules into ~/.claude/rules/ keeping the common/ and
+# Targets:
+#   claude  (default) — Install rules to ~/.claude/rules/
+#   cursor  — Install rules, agents, skills, commands, and MCP to ./.cursor/
+#
+# This script copies rules into the target directory keeping the common/ and
 # language-specific subdirectories intact so that:
 #   1. Files with the same name in common/ and <language>/ don't overwrite
 #      each other.
@@ -16,11 +22,32 @@
 
 set -euo pipefail
 
-RULES_DIR="$(cd "$(dirname "$0")/rules" && pwd)"
-DEST_DIR="${CLAUDE_RULES_DIR:-$HOME/.claude/rules}"
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+RULES_DIR="$SCRIPT_DIR/rules"
 
+# --- Parse --target flag ---
+TARGET="claude"
+if [[ "${1:-}" == "--target" ]]; then
+    if [[ -z "${2:-}" ]]; then
+        echo "Error: --target requires a value (claude or cursor)" >&2
+        exit 1
+    fi
+    TARGET="$2"
+    shift 2
+fi
+
+if [[ "$TARGET" != "claude" && "$TARGET" != "cursor" ]]; then
+    echo "Error: unknown target '$TARGET'. Must be 'claude' or 'cursor'." >&2
+    exit 1
+fi
+
+# --- Usage ---
 if [[ $# -eq 0 ]]; then
-    echo "Usage: $0 <language> [<language> ...]"
+    echo "Usage: $0 [--target <claude|cursor>] <language> [<language> ...]"
+    echo ""
+    echo "Targets:"
+    echo "  claude  (default) — Install rules to ~/.claude/rules/"
+    echo "  cursor  — Install rules, agents, skills, commands, and MCP to ./.cursor/"
     echo ""
     echo "Available languages:"
     for dir in "$RULES_DIR"/*/; do
@@ -31,21 +58,91 @@ if [[ $# -eq 0 ]]; then
     exit 1
 fi
 
-# Always install common rules
-echo "Installing common rules -> $DEST_DIR/common/"
-mkdir -p "$DEST_DIR/common"
-cp -r "$RULES_DIR/common/." "$DEST_DIR/common/"
+# --- Claude target (existing behavior) ---
+if [[ "$TARGET" == "claude" ]]; then
+    DEST_DIR="${CLAUDE_RULES_DIR:-$HOME/.claude/rules}"
 
-# Install each requested language
-for lang in "$@"; do
-    lang_dir="$RULES_DIR/$lang"
-    if [[ ! -d "$lang_dir" ]]; then
-        echo "Warning: rules/$lang/ does not exist, skipping." >&2
-        continue
+    # Always install common rules
+    echo "Installing common rules -> $DEST_DIR/common/"
+    mkdir -p "$DEST_DIR/common"
+    cp -r "$RULES_DIR/common/." "$DEST_DIR/common/"
+
+    # Install each requested language
+    for lang in "$@"; do
+        lang_dir="$RULES_DIR/$lang"
+        if [[ ! -d "$lang_dir" ]]; then
+            echo "Warning: rules/$lang/ does not exist, skipping." >&2
+            continue
+        fi
+        echo "Installing $lang rules -> $DEST_DIR/$lang/"
+        mkdir -p "$DEST_DIR/$lang"
+        cp -r "$lang_dir/." "$DEST_DIR/$lang/"
+    done
+
+    echo "Done. Rules installed to $DEST_DIR/"
+fi
+
+# --- Cursor target ---
+if [[ "$TARGET" == "cursor" ]]; then
+    DEST_DIR=".cursor"
+    CURSOR_SRC="$SCRIPT_DIR/.cursor"
+
+    echo "Installing Cursor configs to $DEST_DIR/"
+
+    # --- Rules ---
+    echo "Installing common rules -> $DEST_DIR/rules/"
+    mkdir -p "$DEST_DIR/rules"
+    # Copy common rules (flattened names like common-coding-style.md)
+    if [[ -d "$CURSOR_SRC/rules" ]]; then
+        for f in "$CURSOR_SRC/rules"/common-*.md; do
+            [[ -f "$f" ]] && cp "$f" "$DEST_DIR/rules/"
+        done
     fi
-    echo "Installing $lang rules -> $DEST_DIR/$lang/"
-    mkdir -p "$DEST_DIR/$lang"
-    cp -r "$lang_dir/." "$DEST_DIR/$lang/"
-done
 
-echo "Done. Rules installed to $DEST_DIR/"
+    # Install language-specific rules
+    for lang in "$@"; do
+        if [[ -d "$CURSOR_SRC/rules" ]]; then
+            found=false
+            for f in "$CURSOR_SRC/rules"/${lang}-*.md; do
+                if [[ -f "$f" ]]; then
+                    cp "$f" "$DEST_DIR/rules/"
+                    found=true
+                fi
+            done
+            if $found; then
+                echo "Installing $lang rules -> $DEST_DIR/rules/"
+            else
+                echo "Warning: no Cursor rules for '$lang' found, skipping." >&2
+            fi
+        fi
+    done
+
+    # --- Agents ---
+    if [[ -d "$CURSOR_SRC/agents" ]]; then
+        echo "Installing agents -> $DEST_DIR/agents/"
+        mkdir -p "$DEST_DIR/agents"
+        cp -r "$CURSOR_SRC/agents/." "$DEST_DIR/agents/"
+    fi
+
+    # --- Skills ---
+    if [[ -d "$CURSOR_SRC/skills" ]]; then
+        echo "Installing skills -> $DEST_DIR/skills/"
+        mkdir -p "$DEST_DIR/skills"
+        cp -r "$CURSOR_SRC/skills/." "$DEST_DIR/skills/"
+    fi
+
+    # --- Commands ---
+    if [[ -d "$CURSOR_SRC/commands" ]]; then
+        echo "Installing commands -> $DEST_DIR/commands/"
+        mkdir -p "$DEST_DIR/commands"
+        cp -r "$CURSOR_SRC/commands/." "$DEST_DIR/commands/"
+    fi
+
+    # --- MCP Config ---
+    if [[ -f "$CURSOR_SRC/mcp.json" ]]; then
+        echo "Installing MCP config -> $DEST_DIR/mcp.json"
+        cp "$CURSOR_SRC/mcp.json" "$DEST_DIR/mcp.json"
+    fi
+
+    echo "Done. Cursor configs installed to $DEST_DIR/"
+fi