[codex] Add local Cloud Upstream sync (#6548)

## Thinking Path

> - Paperclip is the control plane for AI-agent companies.
> - Operators need a path to move local company state toward Paperclip
Cloud without losing local-first control.
> - The Cloud Upstream flow needs API, persistence, CLI, and board UI
surfaces that agree on the same manifest/run model.
> - The existing branch had the feature work plus UX and error-handling
follow-ups.
> - This pull request packages the remaining Cloud Upstream sync work
into one standalone branch.
> - The benefit is an inspectable local-to-cloud sync workflow with
preview, conflicts, activation, and captured UX review states.

## What Changed

- Added Cloud Upstream shared types, server routes/services, and
persisted run schema/migration.
- Added Paperclip Cloud CLI sync helpers and local connection storage.
- Added the Cloud Upstream board UI, settings entry points, query keys,
and UX lab page.
- Added preview/activation checklist behavior, redirect handling,
manifest-only preview support, friendly errors, in-flight hints, and
entity count summaries.

## Verification

- `pnpm --filter @paperclipai/plugin-sdk build`
- `NODE_ENV=test pnpm exec vitest run cli/src/__tests__/cloud.test.ts
server/src/__tests__/instance-settings-routes.test.ts
server/src/__tests__/instance-settings-service.test.ts
ui/src/pages/CloudUpstream.test.tsx
ui/src/components/CompanySettingsSidebar.test.tsx`
- `NODE_ENV=test pnpm exec vitest run
server/src/__tests__/cloud-upstreams.test.ts`

Worktree setup note: the isolated worktree install skipped native sqlite
build scripts, so I copied the already-built local sqlite binding from
the main checkout before running
`server/src/__tests__/cloud-upstreams.test.ts`. The test then passed.

## Risks

- Medium: this adds a database migration and a broad feature path across
CLI/server/UI.
- Merge order: this is the only PR in this split with a DB migration;
merge it before any future Cloud Upstream migration follow-up.
- Mitigation: the PR is based directly on current `origin/master`, has
targeted route/service/UI tests, and keeps the feature behind existing
experimental Cloud Sync settings.

> 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 GPT-5 Codex via `codex_local`, tool-enabled coding session;
exact context window not exposed by this 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, screenshot artifacts are
intentionally omitted per reviewer request
- [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

cli/README.md

@@ -226,6 +226,21 @@ By default, agents run on scheduled heartbeats and event-based triggers (task as
 
 <br/>
 
+## Paperclip Cloud Sync
+
+Cloud upstream sync is behind the `Cloud Sync` experimental setting. Enable it in Instance Settings before pushing.
+
+```bash
+paperclipai cloud connect https://your-stack.paperclip.app
+paperclipai cloud connect https://your-stack.paperclip.app --no-browser
+paperclipai cloud push --company <local-company-id> --dry-run
+paperclipai cloud push --company <local-company-id>
+```
+
+`cloud connect` authorizes the local instance against the target stack and stores the upstream token in the local instance secret store. The default path opens a browser for consent; `--no-browser` uses the device-code flow and prints the verification URL and user code.
+
+`cloud push --dry-run` exports the selected local company, sends a preview bundle to the connected Cloud stack, and exits with code `2` when conflicts need user resolution. A schema mismatch exits with code `3`. Running without `--dry-run` stages chunks idempotently, applies the run, and prints the final summary and recent progress events.
+
 ## Development
 
 ```bash