docs: add README for every content directory

Each directory (agents, hands, integrations, plugins, providers,
scripts, skills) now has a README documenting its TOML format,
current contents, and contribution steps.

agents/README.md

@@ -0,0 +1,63 @@
+# Agents
+
+Autonomous agent definitions for LibreFang. Each agent is a directory containing an `agent.toml` manifest.
+
+## Structure
+
+```
+agents/
+├── hello-world/agent.toml
+├── researcher/agent.toml
+├── coder/agent.toml
+└── ...
+```
+
+## agent.toml Format
+
+```toml
+name = "agent-name"              # Must match directory name
+version = "0.1.0"
+description = "What this agent does"
+author = "author-name"
+module = "builtin:chat"          # Runtime module
+
+[model]
+provider = "default"
+model = "default"
+max_tokens = 4096
+temperature = 0.7
+system_prompt = """Behavioral instructions for the agent."""
+
+[metadata.routing]
+aliases = ["exact match phrases"]
+weak_aliases = ["keyword hints"]
+
+[resources]
+max_llm_tokens_per_hour = 100000
+
+[capabilities]
+tools = ["web_search", "file_read"]
+network = ["*"]
+memory_read = ["*"]
+memory_write = ["self.*"]
+agent_spawn = false
+```
+
+## Current Agents (33)
+
+| Agent | Description |
+|-------|-------------|
+| assistant | Default conversational assistant |
+| researcher | Deep research with web search |
+| coder | Code generation and editing |
+| hello-world | Friendly greeting agent for new users |
+| ... | See each directory for details |
+
+## Adding a New Agent
+
+1. Create `agents/<name>/agent.toml`
+2. Ensure `name` matches the directory name
+3. Run `python scripts/validate.py`
+4. Submit a PR
+
+See [CONTRIBUTING.md](../CONTRIBUTING.md) for the full guide.