Improve external agent invite flow (#6183)

## Thinking Path

> - Paperclip orchestrates AI agents for zero-human companies.
> - Agent creation can happen through local runtimes, managed runtimes,
and external agents that onboard through invites.
> - The old OpenClaw-oriented invite UX lived under company
settings/invites and made a gateway-specific path look like a company
access setting.
> - That hid the broader bring-your-own-agent flow and forced operators
to leave the add-agent modal when adding an external agent.
> - This pull request moves external agent invite generation into the
add-agent modal and makes the copy agent-oriented instead of
OpenClaw-only.
> - The benefit is a clearer agent-first onboarding path while company
invites stay focused on human access.

## What Changed

- Added an external-agent invite branch to the add-agent modal,
including a dedicated prompt result view with Back navigation.
- Added a shared agent onboarding prompt builder and focused modal
coverage for prompt replacement/back navigation.
- Removed the agent invite prompt UI from Company Settings and Company
Invites, leaving Company Invites focused on human access links and
invite history.
- Updated the hidden OpenClaw Gateway runtime hint to direct operators
to the add-agent invite flow instead of presenting it as a blocked
runtime card.
- Updated invite/onboarding docs, storybook coverage, and server-side
onboarding copy toward generic agent language while preserving existing
gateway compatibility.

## Verification

- `pnpm -r typecheck`
- `pnpm build`
- `FAKE_BIN="$(mktemp -d)/bin"; mkdir -p "$FAKE_BIN"; printf
'#!/bin/sh\nexit 1\n' > "$FAKE_BIN/tailscale"; chmod +x
"$FAKE_BIN/tailscale"; PATH="$FAKE_BIN:$PATH" pnpm test:run`
- `pnpm test:run` without the fake `tailscale` shim was also attempted;
it failed only in two pre-existing CLI tailnet fallback tests because
this host has a real Tailscale address (`100.125.202.3`) where those
tests expect no Tailscale.
- Focused confirmation for that host-env issue: `FAKE_BIN=...
PATH="$FAKE_BIN:$PATH" pnpm exec vitest run --project paperclipai
cli/src/__tests__/network-bind.test.ts
cli/src/__tests__/onboard.test.ts`
- Manual UI verification: served UI locally in light mode, opened
add-agent modal, generated external agent prompt, verified the generated
prompt replaces the form and Back returns to the form.

### Screenshots

![Add agent
modal](https://raw.githubusercontent.com/aronprins/paperclip/pr-assets/6183-agent-invites/.github/pr-screenshots/6183/add-agent-modal-light.png)

![External agent invite
form](https://raw.githubusercontent.com/aronprins/paperclip/pr-assets/6183-agent-invites/.github/pr-screenshots/6183/external-agent-invite-form-light.png)

![Generated onboarding prompt replacement
view](https://raw.githubusercontent.com/aronprins/paperclip/pr-assets/6183-agent-invites/.github/pr-screenshots/6183/onboarding-prompt-result-light.png)

## Risks

- Existing OpenClaw gateway compatibility remains, but operators now
discover external agent onboarding from the add-agent modal instead of
company settings.
- Agent invites still appear in the invite history table, so that page
may show agent-scoped invite rows even though it no longer creates agent
onboarding prompts.
- Low migration risk: no schema changes.

> For core feature work, check [`ROADMAP.md`](ROADMAP.md) first and
discuss it in `#dev` before opening the PR. Feature PRs that overlap
with planned core work may need to be redirected — check the roadmap
first. See `CONTRIBUTING.md`.

## Model Used

- OpenAI Codex, GPT-5 coding agent in Codex desktop; tool-enabled
repository, shell, browser, and GitHub workflow. Context window size was
not exposed by the runtime.

## 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
- [x] 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/__tests__/heartbeat-stale-queue-invalidation.test.ts

@@ -2,21 +2,15 @@ import { randomUUID } from "node:crypto";
 import { eq, sql } from "drizzle-orm";
 import { afterAll, afterEach, beforeAll, describe, expect, it, vi } from "vitest";
 import {
-  activityLog,
   agents,
-  agentRuntimeState,
   agentWakeupRequests,
   companies,
-  companySkills,
   createDb,
   documentRevisions,
   documents,
-  heartbeatRunEvents,
   heartbeatRuns,
   issueComments,
   issueDocuments,
-  issueRelations,
-  issueTreeHolds,
   issues,
 } from "@paperclipai/db";
 import { ISSUE_CONTINUATION_SUMMARY_DOCUMENT_KEY } from "@paperclipai/shared";
@@ -89,35 +83,39 @@ async function waitForCondition(fn: () => Promise<boolean>, timeoutMs = 3_000) {
 }
 
 async function cleanupHeartbeatInvalidationFixture(db: ReturnType<typeof createDb>) {
-  for (let attempt = 0; attempt < 5; attempt += 1) {
+  for (let attempt = 0; attempt < 10; attempt += 1) {
     try {
-      await db.delete(companySkills);
-      await db.delete(issueComments);
-      await db.delete(issueDocuments);
-      await db.delete(documentRevisions);
-      await db.delete(documents);
-      await db.delete(issueRelations);
-      await db.delete(issueTreeHolds);
-      await db.delete(issues);
-      await db.delete(heartbeatRunEvents);
-      await db.delete(activityLog);
-      await db.delete(heartbeatRuns);
-      await db.delete(agentWakeupRequests);
-      await db.delete(agentRuntimeState);
-      await db.delete(agents);
-      await db.delete(companies);
+      await db.execute(sql.raw(`
+        TRUNCATE TABLE
+          "company_skills",
+          "issue_comments",
+          "issue_documents",
+          "document_revisions",
+          "documents",
+          "issue_relations",
+          "issue_tree_holds",
+          "issues",
+          "heartbeat_run_events",
+          "activity_log",
+          "heartbeat_runs",
+          "agent_wakeup_requests",
+          "agent_runtime_state",
+          "agents",
+          "companies"
+        RESTART IDENTITY CASCADE
+      `));
       return;
     } catch (error) {
       const isLateCommentRace =
         error instanceof Error &&
         error.message.includes("issue_comments_issue_id_issues_id_fk");
-      if (!isLateCommentRace || attempt === 4) {
+      if (!isLateCommentRace || attempt === 9) {
         throw error;
       }
 
       // Heartbeat completion can write issue-thread comments shortly after the
       // run leaves queued/running. Retry the dependent deletes once those land.
-      await new Promise((resolve) => setTimeout(resolve, 50));
+      await new Promise((resolve) => setTimeout(resolve, 100));
     }
   }
 }