rename(phase 1): CapaKraken → Nexus across code, UI, docs, CI

- @capakraken/* → @nexus/* across 12 packages (root + 11 workspaces),
  1551 import lines migrated via codemod
- User-visible brand strings renamed (emails, page titles, PWA
  manifest, mobile header, MFA backup-codes header, tooltips, signin
  page, invite page, weekly digest, install prompt)
- TOTP issuer "CapaKraken" → "Nexus" (existing secrets still valid;
  re-enrollment relabels them in users' authenticator apps)
- Function rename: assertCapaKrakenDbTarget → assertNexusDbTarget
- LocalStorage migration shim in apps/web/src/app/layout.tsx copies
  capakraken_* → nexus_* on first load (guarded by nexus_migrated_v1
  sentinel; runs once per browser, then never again)
- Service-worker cache name capakraken-v2 → nexus-v2 with one-time
  caches.delete('capakraken-v2') from the same shim
- Email-domain fixtures @capakraken.{dev,app} → @nexus.{dev,app} in
  seed data, e2e specs, SMTP default fallback
- Dockerfile.dev / Dockerfile.prod / all .github/workflows/*.yml
  pnpm --filter @capakraken/* → @nexus/*
- README, CLAUDE.md, LEARNINGS.md, all docs/*.md, .env.example,
  tooling/deploy/.env.production.example brand sweep

Phase 1 deliberately leaves untouched (handled in Phase 3 cutover):
- PostgreSQL DB name "capakraken" and POSTGRES_USER "capakraken"
- Volume names capakraken_pgdata etc.
- Compose project name "capakraken" / "capakraken-prod"
- db-target-guard default expectedDatabase
- env-var CAPAKRAKEN_EXPECTED_DB_NAME
- Container DNS names in docker-compose.ci.yml

Quality gates green: pnpm typecheck (7/7), pnpm test:unit (7/7),
pnpm lint (0 errors), check:exports/imports/architecture all pass.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

docs/showcase-execution-batches.md

@@ -1,7 +1,7 @@
 # Showcase Execution Batches
 
 **Date:** 2026-04-01
-**Purpose:** Canonical execution list for the remaining work to turn CapaKraken into a clean, deterministic, reviewable reference project for disciplined AI-assisted engineering.
+**Purpose:** Canonical execution list for the remaining work to turn Nexus into a clean, deterministic, reviewable reference project for disciplined AI-assisted engineering.
 
 ## How To Use This List
 
@@ -25,6 +25,7 @@ Why first:
 the timeline is the highest-risk UX surface and still not boringly reliable enough for the showcase goal.
 
 Progress note:
+
 - 2026-04-01: overlay cleanup on timeline `viewMode` changes and initial-loading transitions landed with targeted e2e regression coverage for allocation popovers across view switches.
 - 2026-04-01: viewport-change behavior was tightened so point-anchored timeline popovers close on scroll/resize, while element-anchored hover cards remain repositionable; the viewport regression now passes with a non-happy-path e2e.
 - 2026-04-01: active timeline gestures now cancel on window blur / hidden-tab transitions instead of leaving drag or resize state stranded; regression coverage verifies a mid-resize focus loss reverts the preview and allows the next interaction to proceed cleanly.
@@ -37,7 +38,7 @@ Slices:
 - `todo` verify drag, resize, and selection interactions do not compete under rapid input changes
 - `todo` verify SSE first-load, reconnect, and live-update behavior under churn
 - `todo` close explicit edge/failure test gaps in timeline e2e and targeted component tests
-- `todo` continue shrinking [TimelineView.tsx](/home/hartmut/Documents/Copilot/capakraken/apps/web/src/components/timeline/TimelineView.tsx) into narrower ownership units without changing behavior
+- `todo` continue shrinking [TimelineView.tsx](/home/hartmut/Documents/Copilot/nexus/apps/web/src/components/timeline/TimelineView.tsx) into narrower ownership units without changing behavior
 
 Done criteria:
 
@@ -76,7 +77,7 @@ Slices:
 
 - `todo` split resource read orchestration out of `resource-read-shared.ts` into focused read helpers without changing API contracts
 - `todo` keep router files thin and procedure-support focused
-- `todo` continue breaking down large frontend ownership surfaces, starting with [ProjectWizard.tsx](/home/hartmut/Documents/Copilot/capakraken/apps/web/src/components/projects/ProjectWizard.tsx)
+- `todo` continue breaking down large frontend ownership surfaces, starting with [ProjectWizard.tsx](/home/hartmut/Documents/Copilot/nexus/apps/web/src/components/projects/ProjectWizard.tsx)
 - `todo` add focused tests around extracted helpers before broadening further
 
 Done criteria: