chore: import upstream snapshot with attribution

plugins/claude-code/hooks/hooks.json

@@ -0,0 +1,16 @@
+{
+  "hooks": {
+    "SessionEnd": [
+      {
+        "matcher": "*",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "\"${CLAUDE_PLUGIN_ROOT}/hooks/on-session-end.sh\"",
+            "async": true
+          }
+        ]
+      }
+    ]
+  }
+}

plugins/claude-code/hooks/on-session-end.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+# SkillOpt-Sleep SessionEnd hook (async, best-effort, NON-BLOCKING).
+#
+# This does NOT run the optimizer. It only appends a tiny marker so the next
+# nightly cycle knows there is fresh activity to harvest, and (optionally)
+# nudges the user once that a sleep cycle is available. It must never fail the
+# session or spend API budget.
+set -uo pipefail
+
+PLUGIN_ROOT="${CLAUDE_PLUGIN_ROOT:-$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)}"
+STATE_DIR="${HOME}/.skillopt-sleep"
+mkdir -p "$STATE_DIR" 2>/dev/null || exit 0
+
+# Record that a session just ended (cheap; used for "is there new data?").
+printf '%s\t%s\n' "$(date -u +%Y-%m-%dT%H:%M:%SZ)" "${PWD}" \
+  >> "$STATE_DIR/session-end.log" 2>/dev/null || true
+
+exit 0