chore(skills): 引入 agent skills 与锁文件

- superpowers（14 个）：流程纪律（brainstorming/TDD/debug/review 等）
- mobile-android-design：Compose + Material 3 设计实现
- android-clean-architecture：分层/UseCase/Repository/Hilt/Room
- compose-multiplatform-patterns / kotlin-coroutines-flows：KMP 与协程
- skills-lock.json：可复现锁文件；陈旧副本 agent/ 加入 .gitignore

.agents/skills/subagent-driven-development/scripts/task-brief

@@ -0,0 +1,41 @@
+#!/usr/bin/env bash
+# Extract one task's full text from an implementation plan into a file the
+# implementer reads in one call, so the task text never has to be pasted
+# through the controller's context.
+#
+# Usage: task-brief PLAN_FILE TASK_NUMBER [OUTFILE]
+# Default OUTFILE: <repo-root>/.superpowers/sdd/<plan-basename>/task-<N>-brief.md
+# (per plan and per worktree; concurrent runs of the SAME plan in the same
+# working tree share it).
+set -euo pipefail
+
+if [ $# -lt 2 ] || [ $# -gt 3 ]; then
+  echo "usage: task-brief PLAN_FILE TASK_NUMBER [OUTFILE]" >&2
+  exit 2
+fi
+
+plan=$1
+n=$2
+[ -f "$plan" ] || { echo "no such plan file: $plan" >&2; exit 2; }
+
+if [ $# -eq 3 ]; then
+  out=$3
+else
+  dir=$("$(cd "$(dirname "$0")" && pwd)/sdd-workspace" "$plan")
+  out="$dir/task-${n}-brief.md"
+fi
+
+awk -v n="$n" '
+  /^```/ { infence = !infence }
+  !infence && /^#+[ \t]+Task[ \t]+[0-9]+/ {
+    intask = ($0 ~ ("^#+[ \t]+Task[ \t]+" n "([^0-9]|$)"))
+  }
+  intask { print }
+' "$plan" > "$out"
+
+if [ ! -s "$out" ]; then
+  echo "task ${n} not found in ${plan} (no heading matching 'Task ${n}')" >&2
+  exit 3
+fi
+
+echo "wrote ${out}: $(wc -l < "$out" | tr -d ' ') lines"