Add SSH environment support (#4358)

## Thinking Path

> - Paperclip orchestrates AI agents for zero-human companies
> - The environments subsystem already models execution environments,
but before this branch there was no end-to-end SSH-backed runtime path
for agents to actually run work against a remote box
> - That meant agents could be configured around environment concepts
without a reliable way to execute adapter sessions remotely, sync
workspace state, and preserve run context across supported adapters
> - We also need environment selection to participate in normal
Paperclip control-plane behavior: agent defaults, project/issue
selection, route validation, and environment probing
> - Because this capability is still experimental, the UI surface should
be easy to hide and easy to remove later without undoing the underlying
implementation
> - This pull request adds SSH environment execution support across the
runtime, adapters, routes, schema, and tests, then puts the visible
environment-management UI behind an experimental flag
> - The benefit is that we can validate real SSH-backed agent execution
now while keeping the user-facing controls safely gated until the
feature is ready to come out of experimentation

## What Changed

- Added SSH-backed execution target support in the shared adapter
runtime, including remote workspace preparation, skill/runtime asset
sync, remote session handling, and workspace restore behavior after
runs.
- Added SSH execution coverage for supported local adapters, plus remote
execution tests across Claude, Codex, Cursor, Gemini, OpenCode, and Pi.
- Added environment selection and environment-management backend support
needed for SSH execution, including route/service work, validation,
probing, and agent default environment persistence.
- Added CLI support for SSH environment lab verification and updated
related docs/tests.
- Added the `enableEnvironments` experimental flag and gated the
environment UI behind it on company settings, agent configuration, and
project configuration surfaces.

## Verification

- `pnpm exec vitest run
packages/adapters/claude-local/src/server/execute.remote.test.ts
packages/adapters/cursor-local/src/server/execute.remote.test.ts
packages/adapters/gemini-local/src/server/execute.remote.test.ts
packages/adapters/opencode-local/src/server/execute.remote.test.ts
packages/adapters/pi-local/src/server/execute.remote.test.ts`
- `pnpm exec vitest run server/src/__tests__/environment-routes.test.ts`
- `pnpm exec vitest run
server/src/__tests__/instance-settings-routes.test.ts`
- `pnpm exec vitest run ui/src/lib/new-agent-hire-payload.test.ts
ui/src/lib/new-agent-runtime-config.test.ts`
- `pnpm -r typecheck`
- `pnpm build`
- Manual verification on a branch-local dev server:
  - enabled the experimental flag
  - created an SSH environment
  - created a Linux Claude agent using that environment
- confirmed a run executed on the Linux box and synced workspace changes
back

## Risks

- Medium: this touches runtime execution flow across multiple adapters,
so regressions would likely show up in remote session setup, workspace
sync, or environment selection precedence.
- The UI flag reduces exposure, but the underlying runtime and route
changes are still substantial and rely on migration correctness.
- The change set is broad across adapters, control-plane services,
migrations, and UI gating, so review should pay close attention to
environment-selection precedence and remote workspace lifecycle
behavior.

## Model Used

- OpenAI Codex via Paperclip's local Codex adapter, GPT-5-class coding
model with tool use and code execution in the local repo workspace. The
local adapter does not surface a more specific public model version
string in this branch workflow.

## Checklist

- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [ ] If this change affects the UI, I have included before/after
screenshots
- [x] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [x] I will address all Greptile and reviewer comments before
requesting merge

server/src/routes/projects.ts

@@ -13,7 +13,7 @@ import {
 import type { WorkspaceRuntimeDesiredState, WorkspaceRuntimeServiceStateMap } from "@paperclipai/shared";
 import { trackProjectCreated } from "@paperclipai/shared/telemetry";
 import { validate } from "../middleware/validate.js";
-import { projectService, logActivity, secretService, workspaceOperationService } from "../services/index.js";
+import { environmentService, projectService, logActivity, secretService, workspaceOperationService } from "../services/index.js";
 import { conflict } from "../errors.js";
 import { assertCompanyAccess, getActorInfo } from "./authz.js";
 import {
@@ -31,6 +31,7 @@ import {
 import { assertCanManageProjectWorkspaceRuntimeServices } from "./workspace-runtime-service-authz.js";
 import { getTelemetryClient } from "../telemetry.js";
 import { appendWithCap } from "../adapters/utils.js";
+import { assertEnvironmentSelectionForCompany } from "./environment-selection.js";
 
 const WORKSPACE_CONTROL_OUTPUT_MAX_CHARS = 256 * 1024;
 
@@ -40,6 +41,22 @@ export function projectRoutes(db: Db) {
   const secretsSvc = secretService(db);
   const workspaceOperations = workspaceOperationService(db);
   const strictSecretsMode = process.env.PAPERCLIP_SECRETS_STRICT_MODE === "true";
+  const environmentsSvc = environmentService(db);
+
+  async function assertProjectEnvironmentSelection(companyId: string, environmentId: string | null | undefined) {
+    if (environmentId === undefined || environmentId === null) return;
+    await assertEnvironmentSelectionForCompany(environmentsSvc, companyId, environmentId, {
+      allowedDrivers: ["local", "ssh"],
+    });
+  }
+
+  function readProjectPolicyEnvironmentId(policy: unknown): string | null | undefined {
+    if (!policy || typeof policy !== "object" || !("environmentId" in policy)) {
+      return undefined;
+    }
+    const environmentId = (policy as { environmentId?: unknown }).environmentId;
+    return typeof environmentId === "string" || environmentId === null ? environmentId : undefined;
+  }
 
   async function resolveCompanyIdForProjectReference(req: Request) {
     const companyIdQuery = req.query.companyId;
@@ -103,6 +120,10 @@ export function projectRoutes(db: Db) {
     };
 
     const { workspace, ...projectData } = req.body as CreateProjectPayload;
+    await assertProjectEnvironmentSelection(
+      companyId,
+      readProjectPolicyEnvironmentId(projectData.executionWorkspacePolicy),
+    );
     assertNoAgentHostWorkspaceCommandMutation(
       req,
       [
@@ -165,6 +186,10 @@ export function projectRoutes(db: Db) {
       req,
       collectProjectExecutionWorkspaceCommandPaths(body.executionWorkspacePolicy),
     );
+    await assertProjectEnvironmentSelection(
+      existing.companyId,
+      readProjectPolicyEnvironmentId(body.executionWorkspacePolicy),
+    );
     if (typeof body.archivedAt === "string") {
       body.archivedAt = new Date(body.archivedAt);
     }