Add company artifacts page (#7621)

## Thinking Path

> - Paperclip is the open source app people use to manage AI agents for
work.
> - Operators need a way to inspect files and work products created by
agents across a company without opening each issue one by one.
> - The existing issue detail surfaces already show attachments and
outputs, but there was no company-level artifacts index or search-result
affordance for artifact-like records.
> - The backend needed a company-scoped artifacts projection API that
preserves issue/run attribution and safe links back to source records.
> - The UI needed a first-class Artifacts page, sidebar entry, reusable
artifact cards, and deep-link handling that keeps company prefixes
intact.
> - This pull request adds the company artifacts API and page, then
wires artifacts into search and issue output surfaces.
> - The benefit is a single place to browse, filter, and open generated
work products and attachments while preserving company boundaries.

## Linked Issues or Issue Description

Fixes #7622.

Feature request fields:

- Problem/motivation: company operators need a consolidated artifacts
surface for attachments and work products produced by agents.
- Proposed solution: add a company-scoped artifacts projection endpoint,
a board Artifacts route, reusable cards, sidebar navigation, and
artifact search integration.
- Alternatives considered: keep artifact discovery only on individual
issue pages; that forces operators to know the source issue before
finding generated outputs.
- Roadmap alignment: checked `ROADMAP.md`; this is a focused board
UI/API improvement and does not duplicate a listed roadmap item.

## What Changed

- Added shared artifact types and validators.
- Added a company-scoped artifact projection service/API with tests for
attachment/work-product attribution.
- Added Artifacts board UI route, API client, sidebar link, cards,
filters, and storybook coverage.
- Added artifact result handling to company search and issue
output/deep-link flows.
- Rebased the branch onto the latest `public-gh/master` state and
resolved the route-test conflict by preserving both upstream
team-catalog coverage and artifact route coverage.
- Fixed a local Sidebar test helper so it no longer depends on a
runtime-undefined `React.act` export in this dependency install.

## Verification

- `pnpm --filter @paperclipai/ui exec vitest run
src/components/artifacts/ArtifactCard.test.tsx src/api/artifacts.test.ts
src/lib/company-routes.test.ts`
- `pnpm --filter @paperclipai/ui exec vitest run
src/pages/Artifacts.test.tsx src/pages/Search.test.tsx
src/components/Sidebar.test.tsx`
- `pnpm exec vitest run
server/src/__tests__/company-artifacts-service.test.ts
server/src/__tests__/company-search-service.test.ts
server/src/__tests__/company-search-rate-limit-routes.test.ts
server/src/__tests__/issue-agent-mutation-ownership-routes.test.ts`
- Confirmed the PR diff does not include `pnpm-lock.yaml` or
`.github/workflows/*`.
- Duplicate search: no open PRs or issues found for `artifact page
ArtifactCard` in `paperclipai/paperclip`.

Screenshots are intentionally omitted per the internal task instruction
not to add design screenshots or images to this PR unless they are
specifically part of the work. I also attempted browser capture in this
runner, but `agent-browser` failed to launch Chrome and Playwright
Chromium is missing `libatk-1.0.so.0`.

## Risks

- Low-to-medium risk: this adds a new API projection and UI surface, so
attribution/link regressions could affect artifact navigation.
- Company scoping is covered in the new service/API tests.
- No database migrations are included.
- No lockfile or workflow changes are included.

> 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 with tool use and local command
execution. Exact hosted model identifier is not exposed in 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 searched GitHub for duplicate or related PRs and linked
them above
- [x] I have either (a) linked existing issues with `Fixes: #` / `Closes
#` / `Refs #` OR (b) described the issue in-PR following the relevant
issue template
- [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 (intentionally omitted per task instruction; browser capture
unavailable in this runner)
- [x] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [ ] All Paperclip CI gates are green
- [ ] Greptile is 5/5 with no open P2s, recommendations, or follow-ups
- [x] I will address all Greptile and reviewer comments before
requesting merge

---------

Co-authored-by: Paperclip <noreply@paperclip.ing>

ui/storybook/stories/search.stories.tsx

@@ -192,6 +192,7 @@ const fixtureResponse: CompanySearchResponse = {
   results: [...fixtureResults, ...fixtureAgents, ...fixtureProjects],
   countsByType: {
     issue: fixtureResults.length,
+    artifact: 0,
     agent: fixtureAgents.length,
     project: fixtureProjects.length,
   },
@@ -202,11 +203,12 @@ function ScopeTabsPreview({
   active,
   response,
 }: {
-  active: "all" | "issues" | "comments" | "documents" | "agents" | "projects";
+  active: "all" | "issues" | "comments" | "documents" | "artifacts" | "agents" | "projects";
   response: CompanySearchResponse;
 }) {
   const total =
     (response.countsByType.issue ?? 0) +
+    (response.countsByType.artifact ?? 0) +
     (response.countsByType.agent ?? 0) +
     (response.countsByType.project ?? 0);
   const items: PageTabItem[] = [
@@ -214,6 +216,7 @@ function ScopeTabsPreview({
     { value: "issues", label: <ScopeTabLabel label="Issues" count={response.countsByType.issue} /> },
     { value: "comments", label: <ScopeTabLabel label="Comments" count={response.results.filter((result) => result.matchedFields.includes("comment")).length} /> },
     { value: "documents", label: <ScopeTabLabel label="Documents" count={response.results.filter((result) => result.matchedFields.includes("document")).length} /> },
+    { value: "artifacts", label: <ScopeTabLabel label="Artifacts" count={response.countsByType.artifact} /> },
     { value: "agents", label: <ScopeTabLabel label="Agents" count={response.countsByType.agent} /> },
     { value: "projects", label: <ScopeTabLabel label="Projects" count={response.countsByType.project} /> },
   ];
@@ -534,7 +537,7 @@ function SearchStories() {
             <div className="paperclip-story__label">/search</div>
             <h2 className="mt-1 text-lg font-semibold">No results state</h2>
           </div>
-          <SearchPagePreview response={{ ...fixtureResponse, results: [], countsByType: { issue: 0, agent: 0, project: 0 } }} state="empty" query="ghostbuster" />
+          <SearchPagePreview response={{ ...fixtureResponse, results: [], countsByType: { issue: 0, artifact: 0, agent: 0, project: 0 } }} state="empty" query="ghostbuster" />
         </section>
 
         <section className="paperclip-story__frame overflow-hidden p-4">