Add low-trust review containment (#7530)

## Thinking Path

> - Paperclip is a control plane for AI-agent companies, so execution
policy and trust boundaries are part of the product's safety contract.
> - Low-trust review work needs narrower authority than normal
same-company agents because hostile PRs, comments, attachments, and
generated output can carry prompt-injection payloads.
> - The current V1 shape gives trusted workers broad company context,
which is useful for normal execution but too permissive for a reviewer
assigned to hostile content.
> - This branch adds a `low_trust_review` preset, source-trust tagging,
route-level containment, and quarantine handling so low-trust output
does not automatically flow into higher-trust wake context.
> - The branch has been rebased onto current `origin/master`, and the
low-trust migration was renumbered to `0097_low_trust_source_trust.sql`
to avoid collisions with existing `0091` through `0096` migrations.
> - Greptile feedback was addressed by tightening low-trust detection,
preserving project-level trust policy checks, fixing issue-kind
promotion lookup, removing duplicate post-lease isolation assertion,
documenting fail-closed source-trust behavior, bounding ancestry checks,
enforcing runtime issue context for CEOs, awaiting accepted-plan monitor
authorization, and making low-trust issue source-trust tagging atomic.
> - The benefit is a first production slice of deny-by-default review
containment with regression coverage for the main control-plane pivot
surfaces.

Fixes #7531.

## What Changed

- Added shared trust-policy types and validators, plus
database/source-trust fields for issues, comments, documents, and work
products.
- Implemented server enforcement for low-trust issue scope, agent
self-view redaction, secret/plugin/runtime denial paths, promotion
checks, and quarantined continuation/wake context.
- Added focused low-trust regression tests for resolver behavior, source
trust, route authorization, heartbeat preflight ordering, runtime
containment, and quarantine redaction.
- Added board UI affordances for selecting/reviewing the low-trust
preset and surfacing source-trust badges in relevant issue views.
- Added `doc/LOW-TRUST-PRESETS.md`, updated
`doc/SPEC-implementation.md`, and committed the low-trust review
contract plan under `doc/plans/`.
- Rebasing note: the original `0097_low_trust_source_trust.sql`
migration was renamed to `0097_low_trust_source_trust.sql`; the SQL uses
`ADD COLUMN IF NOT EXISTS` so users who already applied the old-numbered
migration are not broken by the renumbered migration.

## Verification

- Rebased branch onto current `origin/master` and force-pushed with
lease to `origin/PAP-10211-low-trust-agent` at head `2719f31e3`.
- Confirmed the PR diff does not include `pnpm-lock.yaml` or
`.github/workflows` changes.
- Resolved upstream UI/comment conflicts by preserving deleted-comment
tombstone behavior and low-trust source-trust badges/metadata.
- Renumbered the low-trust source-trust migration to
`0097_low_trust_source_trust.sql`; the SQL uses `ADD COLUMN IF NOT
EXISTS` so users who already applied an old-numbered copy are not
broken.
- `pnpm exec vitest run ui/src/lib/issue-chat-messages.test.ts
server/src/__tests__/heartbeat-workspace-session.test.ts`
- `pnpm exec vitest run server/src/__tests__/source-trust.test.ts
server/src/__tests__/workspace-runtime-service-authz.test.ts
ui/src/lib/trust-policy-ui.test.ts
ui/src/components/TrustPresetSection.test.tsx`
- `pnpm run typecheck:build-gaps`
- `git diff --check`
- GitHub checks pass on head `2719f31e3`: build, typecheck/release
registry, general tests, serialized server suites, e2e, canary, verify,
policy/review, Socket, and Snyk.
- Greptile Review passes with Confidence Score 5/5 and zero unresolved
Greptile review threads.
- No design screenshots/images were added because the task explicitly
says not to add them unless they are specifically part of the work.

## Risks

- Medium risk: this touches shared trust-policy contracts, server
authorization paths, heartbeat context generation, migration metadata,
and UI preset controls.
- Low-trust containment is intentionally deny-by-default; legitimate
future review workflows may need explicit allowlisted exceptions.
- Plugin/runtime/security surfaces are broad, so regression tests cover
the current known routes but future integrations must route through the
same containment layer.
- The PR is ready for review; GitHub checks are green and Greptile is
5/5.

> 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, tool-enabled shell and GitHub CLI
workflow.

## 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] UI changes are covered by focused tests; no screenshots were added
per task instruction not to add design images unless specifically
required
- [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

---------

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

ui/src/components/NewIssueDialog.tsx

@@ -59,6 +59,7 @@ import {
   ListTree,
   X,
   Eye,
+  ShieldAlert,
   ShieldCheck,
 } from "lucide-react";
 import { cn } from "../lib/utils";
@@ -67,6 +68,7 @@ import { issueStatusText, issueStatusTextDefault, priorityColor, priorityColorDe
 import { MarkdownEditor, type MarkdownEditorRef, type MentionOption } from "./MarkdownEditor";
 import { AgentIcon } from "./AgentIconPicker";
 import { InlineEntitySelector, type InlineEntityOption } from "./InlineEntitySelector";
+import { getTrustPreset } from "../lib/trust-policy-ui";
 
 const DRAFT_KEY = "paperclip:issue-draft";
 const DEBOUNCE_MS = 800;
@@ -1075,6 +1077,7 @@ export function NewIssueDialog() {
   const currentAssignee = selectedAssigneeAgentId
     ? (agents ?? []).find((a) => a.id === selectedAssigneeAgentId)
     : null;
+  const currentAssigneeLowTrust = getTrustPreset(currentAssignee?.permissions) === "low_trust_review";
   const currentProject = orderedProjects.find((project) => project.id === projectId);
   const currentProjectExecutionWorkspacePolicy =
     experimentalSettings?.enableIsolatedWorkspaces === true
@@ -1385,6 +1388,9 @@ export function NewIssueDialog() {
                     <>
                       {assignee ? <AgentIcon icon={assignee.icon} className="h-3.5 w-3.5 shrink-0 text-muted-foreground" /> : null}
                       <span className="truncate">{option.label}</span>
+                      {assignee && getTrustPreset(assignee.permissions) === "low_trust_review" ? (
+                        <ShieldAlert className="ml-auto h-3.5 w-3.5 shrink-0 text-amber-600 dark:text-amber-300" aria-label="Low-trust review agent" />
+                      ) : null}
                     </>
                   );
                 }}
@@ -2030,6 +2036,18 @@ export function NewIssueDialog() {
           </div>
         ) : null}
 
+        {currentAssigneeLowTrust ? (
+          <div
+            data-testid="new-issue-low-trust-assignee-note"
+            className="mx-4 mb-2 flex items-start gap-2 rounded-md border border-amber-300/70 bg-amber-50/90 px-3 py-2 text-xs text-amber-900 dark:border-amber-500/40 dark:bg-amber-500/10 dark:text-amber-100"
+          >
+            <ShieldAlert className="mt-0.5 h-3.5 w-3.5 shrink-0 text-amber-600 dark:text-amber-300" />
+            <span className="leading-snug">
+              Low-trust review agent. It can only act inside its assigned review boundary; issue, project, or run policy defines the concrete scope.
+            </span>
+          </div>
+        ) : null}
+
         {/* Footer */}
         <div className="flex items-center justify-between px-4 py-2.5 border-t border-border shrink-0">
           <Button