feat: agent loop harness with Claude Code plugin support

Generator-evaluator architecture with iterative context-reset for
long-running coding tasks. Ships as a Claude Code plugin — install
with /plugin and use /agent-loop:init, /agent-loop:plan, /agent-loop:run.

install.sh

@@ -0,0 +1,108 @@
+#!/bin/bash
+# Install Agent Loop globally for Claude Code.
+#
+# What this does:
+#   1. Copies the harness to ~/.claude/loop/  (prompts, templates, lib, loop.sh)
+#   2. Installs skills as Claude Code commands at ~/.claude/commands/
+#
+# After install, use /loop-init in any project to get started.
+#
+# Usage:
+#   ./install.sh            # Install
+#   ./install.sh --uninstall  # Remove
+
+set -euo pipefail
+
+CLAUDE_DIR="$HOME/.claude"
+HARNESS_DIR="$CLAUDE_DIR/loop"
+COMMANDS_DIR="$CLAUDE_DIR/commands"
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+
+SKILLS=(loop-init loop-plan loop-run loop-triage)
+
+# --- Colors (if terminal supports them) ---
+if [ -t 1 ]; then
+    GREEN='\033[0;32m'
+    YELLOW='\033[0;33m'
+    RED='\033[0;31m'
+    BOLD='\033[1m'
+    RESET='\033[0m'
+else
+    GREEN='' YELLOW='' RED='' BOLD='' RESET=''
+fi
+
+info()  { echo -e "${GREEN}[loop]${RESET} $*"; }
+warn()  { echo -e "${YELLOW}[loop]${RESET} $*"; }
+error() { echo -e "${RED}[loop]${RESET} $*"; }
+
+# --- Uninstall ---
+if [[ "${1:-}" == "--uninstall" ]]; then
+    info "Uninstalling Agent Loop..."
+
+    if [ -d "$HARNESS_DIR" ]; then
+        rm -rf "$HARNESS_DIR"
+        info "Removed $HARNESS_DIR"
+    fi
+
+    for skill in "${SKILLS[@]}"; do
+        cmd="$COMMANDS_DIR/$skill.md"
+        if [ -f "$cmd" ]; then
+            rm -f "$cmd"
+            info "Removed $cmd"
+        fi
+    done
+
+    info "Done. Per-project .loop/ directories are untouched."
+    exit 0
+fi
+
+# --- Install ---
+info "Installing Agent Loop..."
+
+# Ensure ~/.claude/ exists
+mkdir -p "$CLAUDE_DIR"
+
+# Copy harness (prompts, templates, lib, loop.sh, config example)
+if [ -d "$HARNESS_DIR" ]; then
+    warn "Updating existing install at $HARNESS_DIR"
+    rm -rf "$HARNESS_DIR"
+fi
+
+mkdir -p "$HARNESS_DIR"
+cp -r "$SCRIPT_DIR/prompts"    "$HARNESS_DIR/"
+cp -r "$SCRIPT_DIR/templates"  "$HARNESS_DIR/"
+cp -r "$SCRIPT_DIR/lib"        "$HARNESS_DIR/"
+cp -r "$SCRIPT_DIR/skills"     "$HARNESS_DIR/"
+cp    "$SCRIPT_DIR/loop.sh"    "$HARNESS_DIR/"
+cp    "$SCRIPT_DIR/config.json.example"  "$HARNESS_DIR/"
+cp    "$SCRIPT_DIR/init.sh.example"      "$HARNESS_DIR/"
+chmod +x "$HARNESS_DIR/loop.sh"
+
+info "Harness installed to $HARNESS_DIR"
+
+# Install Claude Code commands
+mkdir -p "$COMMANDS_DIR"
+
+for skill in "${SKILLS[@]}"; do
+    src="$HARNESS_DIR/skills/$skill/SKILL.md"
+    dest="$COMMANDS_DIR/$skill.md"
+
+    if [ -f "$src" ]; then
+        cp "$src" "$dest"
+        info "Installed /$skill command"
+    else
+        warn "Skill not found: $src (skipping)"
+    fi
+done
+
+echo ""
+info "${BOLD}Installation complete.${RESET}"
+echo ""
+echo "  Next steps (inside Claude Code, in any project):"
+echo ""
+echo "    /loop-init        # Set up the loop for your project"
+echo "    /loop-plan        # Generate PRD and sprint contracts"
+echo "    /loop-run         # Run the loop interactively"
+echo ""
+echo "  Or run headless:    .loop/loop.sh"
+echo ""