feat(workspace): Application Workspace foundation (Phase 5 milestone 1)

Every JobApplication gets a dedicated workspace at /applications/{id} — a
surface, not a new data store. It owns no data and duplicates none: CV comes
from the Phase 4 CvVariant lens, analysis/match/interview from the existing
AiWorkspacePanel, documents from Attachments, communication from
Correspondence, activity from JobEvent, stage semantics from JobPipeline. No
career data is copied and nothing here writes.

- GET /api/jobapplications/{id}/workspace: one aggregate read (role, company,
  stage, dates, attached CV variant, cover letter, documents, AI history,
  recent activity) replacing the page fanning out across endpoints
- Next recommended action: ordered rules answering "what do I do next?", the
  core product principle for this phase
- ApplicationWorkspacePage: left nav + linkable ?section=, reusing the existing
  component for each domain; later-milestone sections say so rather than faking
- Entry point from the job dialog via an optional onOpenWorkspace callback —
  the dialog must not depend on router context (it is mounted without a
  <Router> in several suites), so the caller owns navigation
- 8 backend tests (aggregate, CV variant surfacing, counts, activity ordering,
  next-step rules, tenant scoping)

Local: 314 backend, 88/88 frontend (31 suites), tsc clean, production build ok.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

job-tracker-ui/src/applicationWorkspace.ts

@@ -0,0 +1,65 @@
+import { api } from "./api";
+
+// Mirrors WorkspaceOverviewDto. Read-only aggregate — the workspace owns no data.
+export type WorkspaceCv = {
+  variantId: number | null;
+  variantName: string | null;
+  themeId: string | null;
+  hasTailoredCvText: boolean;
+  updatedAtUtc: string | null;
+};
+
+export type WorkspaceActivity = { type: string; detail: string | null; at: string };
+export type WorkspaceNextStep = { key: string; label: string; reason: string; section: string | null };
+
+export type WorkspaceOverview = {
+  id: number;
+  jobTitle: string;
+  company: string | null;
+  location: string | null;
+  salary: string | null;
+  status: string;
+  stageGroup: string;
+  stageOrder: number;
+  dateApplied: string | null;
+  deadline: string | null;
+  followUpAt: string | null;
+  nextAction: string | null;
+  jobUrl: string | null;
+  hasJobDescription: boolean;
+  cv: WorkspaceCv;
+  hasCoverLetter: boolean;
+  documentCount: number;
+  hasPortfolio: boolean;
+  aiInteractionCount: number;
+  lastAiAtUtc: string | null;
+  recentActivity: WorkspaceActivity[];
+  nextStep: WorkspaceNextStep | null;
+};
+
+// Workspace navigation. Sections map to the Phase 5 milestones; each is added as its milestone lands
+// so the workspace is always usable rather than a shell of placeholders.
+export type WorkspaceSectionKey =
+  | "overview" | "job-details" | "analysis" | "match" | "checklist" | "cv" | "cover-letter"
+  | "portfolio" | "documents" | "interview" | "timeline" | "notes" | "communication";
+
+export const WORKSPACE_SECTIONS: { key: WorkspaceSectionKey; label: string; milestone?: number }[] = [
+  { key: "overview", label: "Overview" },
+  { key: "job-details", label: "Job Details" },
+  { key: "analysis", label: "Analysis" },
+  { key: "match", label: "Match" },
+  { key: "checklist", label: "Checklist", milestone: 2 },
+  { key: "cv", label: "CV", milestone: 6 },
+  { key: "cover-letter", label: "Cover Letter", milestone: 7 },
+  { key: "portfolio", label: "Portfolio", milestone: 8 },
+  { key: "documents", label: "Documents" },
+  { key: "interview", label: "Interview Prep" },
+  { key: "timeline", label: "Timeline", milestone: 3 },
+  { key: "notes", label: "Notes", milestone: 3 },
+  { key: "communication", label: "Communication" },
+];
+
+export const applicationWorkspaceApi = {
+  overview: (jobId: number) =>
+    api.get<WorkspaceOverview>(`/jobapplications/${jobId}/workspace`).then((r) => r.data),
+};