feat(skills): import 17 skills from local-dev; fix stale host

Consolidating the divergence between this repo and local-dev's embedded
~/dev/.skills/ (the two had drifted; the 19 overlapping skills were byte-identical).

- Import the 17 skills that existed only in local-dev: discovery-framing,
  stage-gate-review, web-shot, and the 14 superpowers-* skills. This repo is now
  the superset / single source of truth.
- SKILLS_INDEX.md: add rows for the 17.
- install.sh + Taskfile.yml: git.d-ma.be host (was stale gitea.d-ma.be, which
  broke the one-line curl|bash installer post-rename).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

superpowers-brainstorming/scripts/stop-server.sh

@@ -0,0 +1,56 @@
+#!/usr/bin/env bash
+# Stop the brainstorm server and clean up
+# Usage: stop-server.sh <session_dir>
+#
+# Kills the server process. Only deletes session directory if it's
+# under /tmp (ephemeral). Persistent directories (.superpowers/) are
+# kept so mockups can be reviewed later.
+
+SESSION_DIR="$1"
+
+if [[ -z "$SESSION_DIR" ]]; then
+  echo '{"error": "Usage: stop-server.sh <session_dir>"}'
+  exit 1
+fi
+
+STATE_DIR="${SESSION_DIR}/state"
+PID_FILE="${STATE_DIR}/server.pid"
+
+if [[ -f "$PID_FILE" ]]; then
+  pid=$(cat "$PID_FILE")
+
+  # Try to stop gracefully, fallback to force if still alive
+  kill "$pid" 2>/dev/null || true
+
+  # Wait for graceful shutdown (up to ~2s)
+  for i in {1..20}; do
+    if ! kill -0 "$pid" 2>/dev/null; then
+      break
+    fi
+    sleep 0.1
+  done
+
+  # If still running, escalate to SIGKILL
+  if kill -0 "$pid" 2>/dev/null; then
+    kill -9 "$pid" 2>/dev/null || true
+
+    # Give SIGKILL a moment to take effect
+    sleep 0.1
+  fi
+
+  if kill -0 "$pid" 2>/dev/null; then
+    echo '{"status": "failed", "error": "process still running"}'
+    exit 1
+  fi
+
+  rm -f "$PID_FILE" "${STATE_DIR}/server.log"
+
+  # Only delete ephemeral /tmp directories
+  if [[ "$SESSION_DIR" == /tmp/* ]]; then
+    rm -rf "$SESSION_DIR"
+  fi
+
+  echo '{"status": "stopped"}'
+else
+  echo '{"status": "not_running"}'
+fi