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

.cursor/skills/strategic-compact/suggest-compact.sh

@@ -0,0 +1,52 @@
+#!/bin/bash
+# Strategic Compact Suggester
+# Runs on PreToolUse or periodically to suggest manual compaction at logical intervals
+#
+# Why manual over auto-compact:
+# - Auto-compact happens at arbitrary points, often mid-task
+# - Strategic compacting preserves context through logical phases
+# - Compact after exploration, before execution
+# - Compact after completing a milestone, before starting next
+#
+# Hook config (in ~/.claude/settings.json):
+# {
+#   "hooks": {
+#     "PreToolUse": [{
+#       "matcher": "Edit|Write",
+#       "hooks": [{
+#         "type": "command",
+#         "command": "~/.claude/skills/strategic-compact/suggest-compact.sh"
+#       }]
+#     }]
+#   }
+# }
+#
+# Criteria for suggesting compact:
+# - Session has been running for extended period
+# - Large number of tool calls made
+# - Transitioning from research/exploration to implementation
+# - Plan has been finalized
+
+# Track tool call count (increment in a temp file)
+COUNTER_FILE="/tmp/claude-tool-count-$$"
+THRESHOLD=${COMPACT_THRESHOLD:-50}
+
+# Initialize or increment counter
+if [ -f "$COUNTER_FILE" ]; then
+  count=$(cat "$COUNTER_FILE")
+  count=$((count + 1))
+  echo "$count" > "$COUNTER_FILE"
+else
+  echo "1" > "$COUNTER_FILE"
+  count=1
+fi
+
+# Suggest compact after threshold tool calls
+if [ "$count" -eq "$THRESHOLD" ]; then
+  echo "[StrategicCompact] $THRESHOLD tool calls reached - consider /compact if transitioning phases" >&2
+fi
+
+# Suggest at regular intervals after threshold
+if [ "$count" -gt "$THRESHOLD" ] && [ $((count % 25)) -eq 0 ]; then
+  echo "[StrategicCompact] $count tool calls - good checkpoint for /compact if context is stale" >&2
+fi