feat: add Cursor, Codex, and OpenCode harnesses — maximize every AI coding tool

- AGENTS.md: universal cross-tool file read by Claude Code, Cursor, Codex, and OpenCode
- .cursor/: 15 hook events via hooks.json, 16 hook scripts with DRY adapter pattern,
  29 rules (9 common + 20 language-specific) with Cursor YAML frontmatter
- .codex/: reference config.toml, Codex-specific AGENTS.md supplement,
  10 skills ported to .agents/skills/ with openai.yaml metadata
- .opencode/: 3 new tools (format-code, lint-check, git-summary), 3 new hooks
  (shell.env, experimental.session.compacting, permission.ask), expanded instructions,
  version bumped to 1.6.0
- README: fixed Cursor section, added Codex section, added cross-tool parity table
- install.sh: now copies hooks.json + hooks/ for --target cursor

install.sh

@@ -162,6 +162,17 @@ if [[ "$TARGET" == "cursor" ]]; then
         cp -r "$CURSOR_SRC/commands/." "$DEST_DIR/commands/"
     fi
 
+    # --- Hooks ---
+    if [[ -f "$CURSOR_SRC/hooks.json" ]]; then
+        echo "Installing hooks config -> $DEST_DIR/hooks.json"
+        cp "$CURSOR_SRC/hooks.json" "$DEST_DIR/hooks.json"
+    fi
+    if [[ -d "$CURSOR_SRC/hooks" ]]; then
+        echo "Installing hook scripts -> $DEST_DIR/hooks/"
+        mkdir -p "$DEST_DIR/hooks"
+        cp -r "$CURSOR_SRC/hooks/." "$DEST_DIR/hooks/"
+    fi
+
     # --- MCP Config ---
     if [[ -f "$CURSOR_SRC/mcp.json" ]]; then
         echo "Installing MCP config -> $DEST_DIR/mcp.json"