docs: add external documentation site content

Add structured documentation covering quickstart, architecture, core
concepts, API reference, adapter guides, CLI commands, deployment
options, and operator/developer guides.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/adapters/process.md

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+---
+title: Process Adapter
+summary: Generic shell process adapter
+---
+
+# Process Adapter
+
+The `process` adapter executes arbitrary shell commands. Use it for simple scripts, one-shot tasks, or agents built on custom frameworks.
+
+## When to Use
+
+- Running a Python script that calls the Paperclip API
+- Executing a custom agent loop
+- Any runtime that can be invoked as a shell command
+
+## When Not to Use
+
+- If you need session persistence across runs (use `claude_local` or `codex_local`)
+- If the agent needs conversational context between heartbeats
+
+## Configuration
+
+| Field | Type | Required | Description |
+|-------|------|----------|-------------|
+| `command` | string | Yes | Shell command to execute |
+| `cwd` | string | No | Working directory |
+| `env` | object | No | Environment variables |
+| `timeoutSec` | number | No | Process timeout |
+
+## How It Works
+
+1. Paperclip spawns the configured command as a child process
+2. Standard Paperclip environment variables are injected (`PAPERCLIP_AGENT_ID`, `PAPERCLIP_API_KEY`, etc.)
+3. The process runs to completion
+4. Exit code determines success/failure
+
+## Example
+
+An agent that runs a Python script:
+
+```json
+{
+  "adapterType": "process",
+  "adapterConfig": {
+    "command": "python3 /path/to/agent.py",
+    "cwd": "/path/to/workspace",
+    "timeoutSec": 300
+  }
+}
+```
+
+The script can use the injected environment variables to authenticate with the Paperclip API and perform work.