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

ui/src/components/ProjectProperties.tsx

@@ -4,6 +4,7 @@ import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
 import type { Project } from "@paperclipai/shared";
 import { StatusBadge } from "./StatusBadge";
 import { cn, formatDate } from "../lib/utils";
+import { environmentsApi } from "../api/environments";
 import { goalsApi } from "../api/goals";
 import { instanceSettingsApi } from "../api/instanceSettings";
 import { projectsApi } from "../api/projects";
@@ -48,6 +49,7 @@ export type ProjectConfigFieldKey =
   | "env"
   | "execution_workspace_enabled"
   | "execution_workspace_default_mode"
+  | "execution_workspace_environment"
   | "execution_workspace_base_ref"
   | "execution_workspace_branch_template"
   | "execution_workspace_worktree_parent_dir"
@@ -248,6 +250,7 @@ export function ProjectProperties({ project, onUpdate, onFieldUpdate, getFieldSa
     queryFn: () => instanceSettingsApi.getExperimental(),
     retry: false,
   });
+  const environmentsEnabled = experimentalSettings?.enableEnvironments === true;
   const { data: availableSecrets = [] } = useQuery({
     queryKey: selectedCompanyId ? queryKeys.secrets.list(selectedCompanyId) : ["secrets", "none"],
     queryFn: () => secretsApi.list(selectedCompanyId!),
@@ -263,6 +266,11 @@ export function ProjectProperties({ project, onUpdate, onFieldUpdate, getFieldSa
       queryClient.invalidateQueries({ queryKey: queryKeys.secrets.list(selectedCompanyId) });
     },
   });
+  const { data: environments } = useQuery({
+    queryKey: queryKeys.environments.list(selectedCompanyId!),
+    queryFn: () => environmentsApi.list(selectedCompanyId!),
+    enabled: !!selectedCompanyId && environmentsEnabled,
+  });
 
   const linkedGoalIds = project.goalIds.length > 0
     ? project.goalIds
@@ -287,12 +295,16 @@ export function ProjectProperties({ project, onUpdate, onFieldUpdate, getFieldSa
   const isolatedWorkspacesEnabled = experimentalSettings?.enableIsolatedWorkspaces === true;
   const executionWorkspaceDefaultMode =
     executionWorkspacePolicy?.defaultMode === "isolated_workspace" ? "isolated_workspace" : "shared_workspace";
+  const executionWorkspaceEnvironmentId = executionWorkspacePolicy?.environmentId ?? "";
   const executionWorkspaceStrategy = executionWorkspacePolicy?.workspaceStrategy ?? {
     type: "git_worktree",
     baseRef: "",
     branchTemplate: "",
     worktreeParentDir: "",
   };
+  const runSelectableEnvironments = (environments ?? []).filter((environment) =>
+    environment.driver === "local" || environment.driver === "ssh"
+  );
 
   const invalidateProject = () => {
     queryClient.invalidateQueries({ queryKey: queryKeys.projects.detail(project.id) });
@@ -985,6 +997,34 @@ export function ProjectProperties({ project, onUpdate, onFieldUpdate, getFieldSa
                         <div className="text-xs text-muted-foreground">
                           Host-managed implementation: <span className="text-foreground">Git worktree</span>
                         </div>
+                        {environmentsEnabled ? (
+                          <div>
+                            <div className="mb-1 flex items-center gap-1.5">
+                              <label className="flex items-center gap-2 text-xs text-muted-foreground">
+                                <span>Environment</span>
+                                <SaveIndicator state={fieldState("execution_workspace_environment")} />
+                              </label>
+                            </div>
+                            <select
+                              className="w-full rounded border border-border bg-transparent px-2 py-1 text-xs outline-none"
+                              value={executionWorkspaceEnvironmentId}
+                              onChange={(e) =>
+                                commitField(
+                                  "execution_workspace_environment",
+                                  updateExecutionWorkspacePolicy({
+                                    environmentId: e.target.value || null,
+                                  })!,
+                                )}
+                            >
+                              <option value="">No environment</option>
+                              {runSelectableEnvironments.map((environment) => (
+                                <option key={environment.id} value={environment.id}>
+                                  {environment.name} · {environment.driver}
+                                </option>
+                              ))}
+                            </select>
+                          </div>
+                        ) : null}
                         <div>
                           <div className="mb-1 flex items-center gap-1.5">
                             <label className="flex items-center gap-2 text-xs text-muted-foreground">