feat(ui): turn Artifacts V1 on for every instance and hide its toggle (#19164)

## Thinking Path

> - Paperclip is the open source app people use to manage AI agents for
work
> - Artifacts show the output of agent work on the Artifacts page, in
the panel Artifacts tab, and in the task thread
> - #17228 added the Artifacts V1 presentation behind an experimental
setting that is off by default
> - The presentation is now ready for all users, so an opt-in toggle is
no longer necessary
> - A new default alone does not reach all instances, because each
experimental write persists every flag
> - This pull request removes the toggle and turns V1 on for every
instance
> - The benefit is one artifact presentation for all users, with an off
switch for hosting operators

## Linked Issues or Issue Description

Refs #17228
Refs #17263

**Is your feature request related to a problem? Please describe.**
Artifacts V1 shows only on instances where an admin turned on an
experimental setting. Other users see the previous cards.

**Describe the solution you would like**
Show Artifacts V1 on all instances. Remove the toggle from Experimental
settings.

**Describe alternatives you have considered**
A new default without a change to the hook. This does not work, because
many instances have a stored false that nobody chose, and no toggle
would remain to change it.

## What Changed

- Removed the Artifacts V1 card from Instance Settings, Experimental.
- Changed `enableArtifactsV1` to default on in the schema, the feature
catalog, and the settings service.
- Changed `resolveArtifactsV1Enabled` to ignore a stored false. It
honours false only when the value comes from managed config.
- Kept the flag and the previous cards, so a hosting operator can hold
V1 off.
- Kept the key in the Cloud staging list, so a managed false does not
hold V1 off on staging.
- Updated unit tests, the Artifacts V1 plan, and the directions-lab
Today reference.
- Moved the attachment and upload e2e specs and the runner download
helper to the V1 rows.
- Added V1 tests for a Markdown review: expansion, deep link, and open,
raw and download actions.

## Verification

- `cd ui && npx vitest run`: one test file failed before its fix. That
file tests the previous cards, and it now mocks the hook to off. I reran
it with the other changed UI tests, and they pass. I did not repeat the
full UI run after the fix.
- `npx playwright test --config tests/e2e/playwright.config.ts
tests/e2e/text-attachment-tabs.spec.ts
tests/e2e/artifact-uploads.spec.ts
tests/e2e/artifact-tab-arrival.spec.ts`: 10 tests pass on V1.
- `tests/e2e/cloud-auth.spec.ts` failed once in CI on a task heading. It
does not touch artifacts, and 10 local runs pass.
- `cd server && npx vitest run src/__tests__/instance-settings`: 183
tests pass.
- `cd packages/shared && npx vitest run src/feature-catalog.test.ts
src/validators/instance.test.ts`: 35 tests pass.
- `pnpm run check:token-gates` and the `ui` and `server` typechecks
pass. I did not run the full repository check.
- In the artifact directions lab, with no stored settings, the Today
right panel renders the V1 rows.
- I did not test this on a live instance. After merge, confirm on
staging that the Experimental page has no Artifacts V1 card and that all
three surfaces show V1.

## Risks

- All users see V1 after the next release, not only staging users. To
revert, revert this pull request.
- Users cannot turn V1 off. Only a hosting operator can, through managed
config, and not on Cloud staging.
- An instance with a managed `enableArtifactsV1: false` stays on the
previous cards. The cloud harness source has no reference to this key,
but I cannot read the live fleet configuration.
- V1 surfaces render before settings load. An operator-held instance can
briefly show V1 before the previous cards.
- Admins who use the API can still write the flag. The write has no
effect on unmanaged instances.

> 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

- Anthropic Claude Opus 5.5 (`claude-opus-5-5`) in Claude Code, with
tool use and code execution.

## 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 not referenced internal/instance-local Paperclip issues or
links (only public GitHub `#NNN` / `github.com/paperclipai/paperclip`
URLs)
- [x] My branch name describes the change (e.g. `docs/...`, `fix/...`)
and contains no internal Paperclip ticket id or instance-derived details
- [x] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [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

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

server/src/__tests__/instance-settings-cloud-defaults.test.ts

@@ -20,6 +20,14 @@ function managedConfig(features: ManagedInstanceConfig["features"] = {}): Manage
   };
 }
 
+describe("Artifacts V1 defaults", () => {
+  it("is on for self-hosted and Cloud instances that never stored it", () => {
+    expect(INSTANCE_FEATURE_CATALOG.enableArtifactsV1).toMatchObject({ cloudDefault: true, selfHostedDefault: true });
+    expect(applyCloudCatalogDefaults(normalizeExperimentalSettings({}), {}, null).enableArtifactsV1).toBe(true);
+    expect(applyCloudCatalogDefaults(normalizeExperimentalSettings({}), {}, managedConfig()).enableArtifactsV1).toBe(true);
+  });
+});
+
 describe("applyCloudCatalogDefaults", () => {
   it("pins the catalog so this rule has something to guard", () => {
     // The rule exists for flags that default on for self-hosted and off for

server/src/__tests__/instance-settings-service.test.ts

@@ -110,7 +110,7 @@ describe("instance settings service", () => {
       enableMuse: false,
       enableGrokBot: false,
       enableCombinedInboxTasks: false,
-      enableArtifactsV1: false,
+      enableArtifactsV1: true,
       enableChatConnectors: false,
       enableGitHubReviewBots: false,
       enableMemoryConnectors: false,

server/src/services/instance-settings.ts

@@ -268,7 +268,7 @@ export function normalizeExperimentalSettings(raw: unknown): InstanceExperimenta
       enableCases: parsed.data.enableCases ?? false,
       enableAgentChat: parsed.data.enableAgentChat ?? false,
       enableCombinedInboxTasks: parsed.data.enableCombinedInboxTasks ?? false,
-      enableArtifactsV1: parsed.data.enableArtifactsV1 ?? false,
+      enableArtifactsV1: parsed.data.enableArtifactsV1 ?? true,
       enableConferenceRoomChat: parsed.data.enableConferenceRoomChat ?? false,
       enableClassicTaskInterface: parsed.data.enableClassicTaskInterface ?? false,
       enableIssuePlanDecompositions: parsed.data.enableIssuePlanDecompositions ?? false,
@@ -325,7 +325,7 @@ export function normalizeExperimentalSettings(raw: unknown): InstanceExperimenta
     enableCases: false,
     enableAgentChat: false,
     enableCombinedInboxTasks: false,
-    enableArtifactsV1: false,
+    enableArtifactsV1: true,
     enableConferenceRoomChat: false,
     enableClassicTaskInterface: false,
     enableIssuePlanDecompositions: false,