feat: implement multi-user access and invite flows (#3784)

## Thinking Path

> - Paperclip is the control plane for autonomous AI companies.
> - V1 needs to stay local-first while also supporting shared,
authenticated deployments.
> - Human operators need real identities, company membership, invite
flows, profile surfaces, and company-scoped access controls.
> - Agents and operators also need the existing issue, inbox, workspace,
approval, and plugin flows to keep working under those authenticated
boundaries.
> - This branch accumulated the multi-user implementation, follow-up QA
fixes, workspace/runtime refinements, invite UX improvements,
release-branch conflict resolution, and review hardening.
> - This pull request consolidates that branch onto the current `master`
branch as a single reviewable PR.
> - The benefit is a complete multi-user implementation path with tests
and docs carried forward without dropping existing branch work.

## What Changed

- Added authenticated human-user access surfaces: auth/session routes,
company user directory, profile settings, company access/member
management, join requests, and invite management.
- Added invite creation, invite landing, onboarding, logo/branding,
invite grants, deduped join requests, and authenticated multi-user E2E
coverage.
- Tightened company-scoped and instance-admin authorization across
board, plugin, adapter, access, issue, and workspace routes.
- Added profile-image URL validation hardening, avatar preservation on
name-only profile updates, and join-request uniqueness migration cleanup
for pending human requests.
- Added an atomic member role/status/grants update path so Company
Access saves no longer leave partially updated permissions.
- Improved issue chat, inbox, assignee identity rendering,
sidebar/account/company navigation, workspace routing, and execution
workspace reuse behavior for multi-user operation.
- Added and updated server/UI tests covering auth, invites, membership,
issue workspace inheritance, plugin authz, inbox/chat behavior, and
multi-user flows.
- Merged current `public-gh/master` into this branch, resolved all
conflicts, and verified no `pnpm-lock.yaml` change is included in this
PR diff.

## Verification

- `pnpm exec vitest run server/src/__tests__/issues-service.test.ts
ui/src/components/IssueChatThread.test.tsx ui/src/pages/Inbox.test.tsx`
- `pnpm run preflight:workspace-links && pnpm exec vitest run
server/src/__tests__/plugin-routes-authz.test.ts`
- `pnpm exec vitest run server/src/__tests__/plugin-routes-authz.test.ts
server/src/__tests__/workspace-runtime-service-authz.test.ts
server/src/__tests__/access-validators.test.ts`
- `pnpm exec vitest run
server/src/__tests__/authz-company-access.test.ts
server/src/__tests__/routines-routes.test.ts
server/src/__tests__/sidebar-preferences-routes.test.ts
server/src/__tests__/approval-routes-idempotency.test.ts
server/src/__tests__/openclaw-invite-prompt-route.test.ts
server/src/__tests__/agent-cross-tenant-authz-routes.test.ts
server/src/__tests__/routines-e2e.test.ts`
- `pnpm exec vitest run server/src/__tests__/auth-routes.test.ts
ui/src/pages/CompanyAccess.test.tsx`
- `pnpm --filter @paperclipai/shared typecheck && pnpm --filter
@paperclipai/db typecheck && pnpm --filter @paperclipai/server
typecheck`
- `pnpm --filter @paperclipai/shared typecheck && pnpm --filter
@paperclipai/server typecheck`
- `pnpm --filter @paperclipai/ui typecheck`
- `pnpm db:generate`
- `npx playwright test --config tests/e2e/playwright.config.ts --list`
- Confirmed branch has no uncommitted changes and is `0` commits behind
`public-gh/master` before PR creation.
- Confirmed no `pnpm-lock.yaml` change is staged or present in the PR
diff.

## Risks

- High review surface area: this PR contains the accumulated multi-user
branch plus follow-up fixes, so reviewers should focus especially on
company-boundary enforcement and authenticated-vs-local deployment
behavior.
- UI behavior changed across invites, inbox, issue chat, access
settings, and sidebar navigation; no browser screenshots are included in
this branch-consolidation PR.
- Plugin install, upgrade, and lifecycle/config mutations now require
instance-admin access, which is intentional but may change expectations
for non-admin board users.
- A join-request dedupe migration rejects duplicate pending human
requests before creating unique indexes; deployments with unusual
historical duplicates should review the migration behavior.
- Company member role/status/grant saves now use a new combined
endpoint; older separate endpoints remain for compatibility.
- Full production build was not run locally in this heartbeat; CI should
cover the full matrix.

## Model Used

- OpenAI Codex coding agent, GPT-5-based model, CLI/tool-use
environment. Exact deployed model identifier and context window were 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 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

Note on screenshots: this is a branch-consolidation PR for an
already-developed multi-user branch, and no browser screenshots were
captured during this heartbeat.

---------

Co-authored-by: dotta <dotta@example.com>
Co-authored-by: Paperclip <noreply@paperclip.ing>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

ui/src/components/ExecutionParticipantPicker.tsx

@@ -1,6 +1,10 @@
-import { useState } from "react";
+import { useMemo, useState } from "react";
 import type { Agent, Issue } from "@paperclipai/shared";
+import { useQuery } from "@tanstack/react-query";
+import { accessApi } from "../api/access";
 import { formatAssigneeUserLabel } from "../lib/assignees";
+import { buildCompanyUserInlineOptions, buildCompanyUserLabelMap } from "../lib/company-members";
+import { queryKeys } from "../lib/queryKeys";
 import { sortAgentsByRecency, getRecentAssigneeIds } from "../lib/recent-assignees";
 import {
   buildExecutionPolicy,
@@ -34,14 +38,27 @@ export function ExecutionParticipantPicker({
   const reviewerValues = stageParticipantValues(issue.executionPolicy, "review");
   const approverValues = stageParticipantValues(issue.executionPolicy, "approval");
   const values = stageType === "review" ? reviewerValues : approverValues;
+  const { data: companyMembers } = useQuery({
+    queryKey: queryKeys.access.companyUserDirectory(issue.companyId),
+    queryFn: () => accessApi.listUserDirectory(issue.companyId),
+    enabled: !!issue.companyId,
+  });
 
   const sortedAgents = sortAgentsByRecency(
     agents.filter((a) => a.status !== "terminated"),
     getRecentAssigneeIds(),
   );
+  const userLabelMap = useMemo(
+    () => buildCompanyUserLabelMap(companyMembers?.users),
+    [companyMembers?.users],
+  );
+  const otherUserOptions = useMemo(
+    () => buildCompanyUserInlineOptions(companyMembers?.users, { excludeUserIds: [currentUserId, issue.createdByUserId] }),
+    [companyMembers?.users, currentUserId, issue.createdByUserId],
+  );
 
   const userLabel = (userId: string | null | undefined) =>
-    formatAssigneeUserLabel(userId, currentUserId);
+    formatAssigneeUserLabel(userId, currentUserId, userLabelMap);
   const creatorUserLabel = userLabel(issue.createdByUserId);
 
   const agentName = (id: string) => {
@@ -138,6 +155,24 @@ export function ExecutionParticipantPicker({
               {creatorUserLabel ?? "Requester"}
             </button>
           )}
+          {otherUserOptions
+            .filter((option) => {
+              if (!search.trim()) return true;
+              return `${option.label} ${option.searchText ?? ""}`.toLowerCase().includes(search.toLowerCase());
+            })
+            .map((option) => (
+              <button
+                key={option.id}
+                className={cn(
+                  "flex items-center gap-2 w-full px-2 py-1.5 text-xs rounded hover:bg-accent/50",
+                  values.includes(option.id) && "bg-accent",
+                )}
+                onClick={() => toggle(option.id)}
+              >
+                <User className="h-3 w-3 shrink-0 text-muted-foreground" />
+                {option.label}
+              </button>
+            ))}
           {sortedAgents
             .filter((agent) => {
               if (!search.trim()) return true;