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

packages/db/src/migrations/0067_agent_default_environment.sql

@@ -0,0 +1,3 @@
+ALTER TABLE "agents" ADD COLUMN "default_environment_id" uuid;
+ALTER TABLE "agents" ADD CONSTRAINT "agents_default_environment_id_environments_id_fk" FOREIGN KEY ("default_environment_id") REFERENCES "public"."environments"("id") ON DELETE set null ON UPDATE no action;
+CREATE INDEX "agents_company_default_environment_idx" ON "agents" USING btree ("company_id","default_environment_id");

packages/db/src/migrations/0068_environment_local_driver_unique.sql

@@ -0,0 +1,2 @@
+DROP INDEX IF EXISTS "environments_company_driver_idx";--> statement-breakpoint
+CREATE UNIQUE INDEX IF NOT EXISTS "environments_company_driver_idx" ON "environments" USING btree ("company_id","driver") WHERE "driver" = 'local';

packages/db/src/migrations/meta/_journal.json

@@ -470,6 +470,20 @@
       "when": 1776903901000,
       "tag": "0066_issue_tree_holds",
       "breakpoints": true
+    },
+    {
+      "idx": 67,
+      "version": "7",
+      "when": 1776904200000,
+      "tag": "0067_agent_default_environment",
+      "breakpoints": true
+    },
+    {
+      "idx": 68,
+      "version": "7",
+      "when": 1776959400000,
+      "tag": "0068_environment_local_driver_unique",
+      "breakpoints": true
     }
   ]
 }

packages/db/src/schema/agents.ts

@@ -9,6 +9,7 @@ import {
   index,
 } from "drizzle-orm/pg-core";
 import { companies } from "./companies.js";
+import { environments } from "./environments.js";
 
 export const agents = pgTable(
   "agents",
@@ -25,6 +26,7 @@ export const agents = pgTable(
     adapterType: text("adapter_type").notNull().default("process"),
     adapterConfig: jsonb("adapter_config").$type<Record<string, unknown>>().notNull().default({}),
     runtimeConfig: jsonb("runtime_config").$type<Record<string, unknown>>().notNull().default({}),
+    defaultEnvironmentId: uuid("default_environment_id").references(() => environments.id, { onDelete: "set null" }),
     budgetMonthlyCents: integer("budget_monthly_cents").notNull().default(0),
     spentMonthlyCents: integer("spent_monthly_cents").notNull().default(0),
     pauseReason: text("pause_reason"),
@@ -38,5 +40,6 @@ export const agents = pgTable(
   (table) => ({
     companyStatusIdx: index("agents_company_status_idx").on(table.companyId, table.status),
     companyReportsToIdx: index("agents_company_reports_to_idx").on(table.companyId, table.reportsTo),
+    companyDefaultEnvironmentIdx: index("agents_company_default_environment_idx").on(table.companyId, table.defaultEnvironmentId),
   }),
 );

packages/db/src/schema/environments.ts

@@ -1,3 +1,4 @@
+import { sql } from "drizzle-orm";
 import { index, jsonb, pgTable, text, timestamp, uniqueIndex, uuid } from "drizzle-orm/pg-core";
 import { companies } from "./companies.js";
 
@@ -17,7 +18,9 @@ export const environments = pgTable(
   },
   (table) => ({
     companyStatusIdx: index("environments_company_status_idx").on(table.companyId, table.status),
-    companyDriverIdx: uniqueIndex("environments_company_driver_idx").on(table.companyId, table.driver),
+    companyDriverIdx: uniqueIndex("environments_company_driver_idx")
+      .on(table.companyId, table.driver)
+      .where(sql`${table.driver} = 'local'`),
     companyNameIdx: index("environments_company_name_idx").on(table.companyId, table.name),
   }),
 );