feat: Add agent preview integration with auto-teardown and simplified commands

- Add agentId label to preview containers (cw.agent-id) for tracking
- Add startForAgent/stopByAgentId methods to PreviewManager
- Auto-teardown: previews torn down on agent:stopped event
- Conditional preview prompt injection for execute/refine/discuss agents
- Agent-simplified CLI: cw preview start/stop --agent <id>
- cw preview setup command with --auto mode for guided config generation
- hasPreviewConfig hint on cw project register output
- New tRPC procedures: startPreviewForAgent, stopPreviewByAgent

docs/preview.md

@@ -268,6 +268,7 @@ All preview containers get `cw.*` labels for metadata retrieval:
 | `cw.port` | Gateway port |
 | `cw.preview-id` | Nanoid for this deployment |
 | `cw.mode` | `"preview"` or `"dev"` |
+| `cw.agent-id` | Agent ID (optional, set when started via `--agent`) |
 
 ### Compose Project Naming
 
@@ -321,24 +322,62 @@ See [Setting Up Preview Deployments](#setting-up-preview-deployments-for-a-proje
 3. Branch is derived from `phaseBranchName(initiative.branch, phase.name)`
 4. Errors are caught and logged (best-effort, never blocks the phase transition)
 
+## Agent Integration
+
+Agents can spin up and tear down preview deployments using simplified commands that only require their agent ID — the server resolves initiative, project, branch, and mode automatically.
+
+### Agent-Simplified Commands
+
+When an agent has a `<preview_deployments>` section in its prompt (injected automatically if the initiative's project has `.cw-preview.yml`), it can use:
+
+```
+cw preview start --agent <agentId>    # Server resolves everything, starts dev mode
+cw preview stop --agent <agentId>     # Stops all previews for this agent
+```
+
+### Prompt Injection
+
+Preview instructions are automatically appended to agent prompts when all conditions are met:
+1. Agent mode is `execute`, `refine`, or `discuss`
+2. Agent has an `initiativeId`
+3. Initiative has exactly one linked project
+4. Project clone directory contains `.cw-preview.yml`
+
+The injected `<preview_deployments>` block includes prefilled `cw preview start/stop --agent <agentId>` commands.
+
+### Agent ID Label
+
+Previews started with `--agent` receive a `cw.agent-id` Docker container label. This enables:
+- **Auto-teardown**: When an agent stops (`agent:stopped` event), all previews labeled with its ID are automatically torn down (best-effort).
+- **Agent-scoped stop**: `cw preview stop --agent <id>` finds and stops previews by label.
+
+### Setup Command
+
+`cw preview setup` prints inline setup instructions for `.cw-preview.yml`. With `--auto --project <id>`, it creates an initiative and spawns a refine agent to analyze the project and generate the config file.
+
 ## tRPC Procedures
 
 | Procedure | Type | Input |
 |-----------|------|-------|
-| `startPreview` | mutation | `{initiativeId, phaseId?, projectId, branch, mode?, worktreePath?}` |
+| `startPreview` | mutation | `{initiativeId, phaseId?, projectId, branch, mode?, worktreePath?, agentId?}` |
+| `startPreviewForAgent` | mutation | `{agentId}` |
 | `stopPreview` | mutation | `{previewId}` |
+| `stopPreviewByAgent` | mutation | `{agentId}` |
 | `listPreviews` | query | `{initiativeId?}` |
 | `getPreviewStatus` | query | `{previewId}` |
 
-`mode` defaults to `'preview'`. Set to `'dev'` with a `worktreePath` for dev mode.
+`mode` defaults to `'preview'`. Set to `'dev'` with a `worktreePath` for dev mode. `startPreviewForAgent` always uses dev mode.
 
 ## CLI Commands
 
 ```
-cw preview start --initiative <id> --project <id> --branch <branch> [--phase <id>] [--mode preview|dev]
+cw preview start --initiative <id> --project <id> --branch <branch> [--phase <id>]
+cw preview start --agent <id>
 cw preview stop <previewId>
+cw preview stop --agent <id>
 cw preview list [--initiative <id>]
 cw preview status <previewId>
+cw preview setup [--auto --project <id> [--provider <name>]]
 ```
 
 ## Frontend