feat: add OpenProse plugin skills

extensions/open-prose/skills/prose/lib/user-memory.prose

@@ -0,0 +1,93 @@
+# User Memory
+# A persistent agent that learns and remembers across all your projects
+#
+# Usage:
+#   prose run @openprose/lib/user-memory --backend sqlite+
+#
+# Recommended backend: sqlite+ (for durable cross-project persistence)
+#
+# Modes:
+#   teach: Add new knowledge
+#   query: Ask questions
+#   reflect: Summarize what you know about a topic
+#
+# The memory agent accumulates knowledge over time. Each interaction
+# builds on previous ones. Use liberally—teach it your preferences,
+# decisions, patterns, and lessons learned.
+
+input mode: "Mode: teach | query | reflect"
+input content: "What to teach, ask, or reflect on"
+
+# ============================================================
+# Agent
+# ============================================================
+
+agent memory:
+  model: opus
+  persist: user
+  prompt: """
+    You are the user's personal knowledge base, persisting across all projects.
+
+    You remember:
+    - Technical preferences (languages, frameworks, patterns they prefer)
+    - Architectural decisions and their reasoning
+    - Coding conventions and style preferences
+    - Mistakes they've learned from (and what to do instead)
+    - Domain knowledge they've accumulated
+    - Project contexts and how they relate
+    - Tools, libraries, and configurations they use
+    - Opinions and strong preferences
+
+    Principles:
+    - Be concise. Store knowledge efficiently.
+    - Prioritize actionable knowledge over trivia.
+    - Note confidence levels when uncertain.
+    - Update previous knowledge when new info contradicts it.
+    - Connect related pieces of knowledge.
+  """
+
+# ============================================================
+# Modes
+# ============================================================
+
+if **mode is teach**:
+  output result = resume: memory
+    prompt: """
+      Learn and remember this:
+
+      {content}
+
+      Integrate with your existing knowledge. If this updates or
+      contradicts something you knew before, note the change.
+
+      Respond with a brief confirmation of what you learned.
+    """
+
+elif **mode is query**:
+  output result = resume: memory
+    prompt: """
+      Question: {content}
+
+      Answer from your accumulated knowledge about this user.
+
+      If you know relevant context, share it.
+      If you're uncertain, say so.
+      If you don't know, say that clearly.
+    """
+
+elif **mode is reflect**:
+  output result = resume: memory
+    prompt: """
+      Reflect on your knowledge about: {content}
+
+      Summarize:
+      - What you know about this topic
+      - How confident you are
+      - Gaps in your knowledge
+      - What would be valuable to learn
+
+      Be honest about the limits of what you know.
+    """
+
+else:
+  throw "Unknown mode: {mode}. Use: teach, query, or reflect"