Initial Arka plugin registry: Official plugins mirror + Arka-signed index

11 plugins from github.com/librefang/librefang-registry plugins/.
index.json / index.json.sig are signed with Arka's Ed25519 key
(not upstream stats.librefang.ai). Private key is not in this repo.

plugins/user-profile/README.md

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+# user-profile
+
+Persistent user profiling from conversation patterns. Builds a profile of user expertise areas, communication style, and technical level, then injects it as context so agents can personalize responses.
+
+## How it works
+
+**After each turn**, the plugin analyzes user messages to update the profile:
+
+- **Expertise areas** -- extracts technical keywords and tracks frequency (top 20 retained)
+- **Communication style** -- running average of message lengths (brief / moderate / detailed)
+- **Technical level** -- scored from signals like code blocks, version numbers, tech abbreviations, and question patterns (beginner / intermediate / advanced)
+- **Question ratio** -- fraction of user messages containing questions
+
+**On ingest**, once the profile has at least 5 interactions, the plugin returns a compact profile summary as a memory fragment: `expertise=python,devops; style=detailed; level=advanced`.
+
+## Hooks
+
+| Hook | Script | Description |
+|------|--------|-------------|
+| ingest | `hooks/ingest.py` | Returns the profile summary as a memory fragment (after 5+ interactions) |
+| after_turn | `hooks/after_turn.py` | Analyzes user messages to update the profile |
+
+## Storage
+
+Profiles are stored at `~/.librefang/plugins/user-profile/{agent_id}.json`.
+
+## Usage
+
+Installed automatically when enabled in agent configuration.