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/demand-assignment-migration-cutover.md

@@ -24,9 +24,9 @@ pnpm db:readiness:demand-assignment --write-artifacts
 Supporting commands:
 
 ```bash
-pnpm --filter @capakraken/db db:audit:demand-assignment --json --fail-on-blockers
-pnpm --filter @capakraken/db db:backfill:demand-assignment --json --fail-on-blockers
-pnpm --filter @capakraken/db db:backfill:demand-assignment --apply
+pnpm --filter @nexus/db db:audit:demand-assignment --json --fail-on-blockers
+pnpm --filter @nexus/db db:backfill:demand-assignment --json --fail-on-blockers
+pnpm --filter @nexus/db db:backfill:demand-assignment --apply
 ```
 
 `pnpm db:readiness:demand-assignment` fails with a non-zero exit code when the workspace is not ready for `--apply`. Use `--allow-blockers` only when collecting review artifacts before remediation.
@@ -86,7 +86,7 @@ No production backfill should run from an ad hoc shell session without the saved
 
 ### Stage 3: Apply Backfill
 
-- run `pnpm --filter @capakraken/db db:backfill:demand-assignment --apply`
+- run `pnpm --filter @nexus/db db:backfill:demand-assignment --apply`
 - immediately rerun `pnpm db:readiness:demand-assignment --write-artifacts`
 - require the post-apply readiness report to remain `go`
 
@@ -129,7 +129,7 @@ The latest workspace readiness run on `2026-03-13T20:10:43.050Z` reported:
 - dry-run creates: `0` demand, `0` assignment
 - `goNoGo: "go"`
 
-The first real `pnpm --filter @capakraken/db db:backfill:demand-assignment --apply --json` was executed on `2026-03-13` and completed as a no-op:
+The first real `pnpm --filter @nexus/db db:backfill:demand-assignment --apply --json` was executed on `2026-03-13` and completed as a no-op:
 
 - `demandCreates: 0`
 - `assignmentCreates: 0`
@@ -177,6 +177,7 @@ As of `2026-03-14`, the split persistence migration is fully complete through St
 ### Facade Retirement (Complete)
 
 The former compatibility facades have been renamed to clean domain names:
+
 - `update-allocation-with-compatibility` → `update-allocation-entry`
 - `delete-allocation-facade-entry` → `delete-allocation-entry`
 - `fill-open-demand-with-compatibility` → `fill-open-demand`
@@ -184,7 +185,7 @@ The former compatibility facades have been renamed to clean domain names:
 
 All `AllocationFacade*` type prefixes have been replaced with `AllocationEntry*`. All `compatibilityId` and `source` fields have been removed from booking interfaces. Variable names like `demandRequirementByCompatibilityId` and `existingFacade` have been renamed to `demandRequirementById` and `resolved`. Test descriptions referencing "compatibility" have been updated.
 
-No legacy *compatibility* naming (e.g. `compatibilityId`, `AllocationFacade*`, `WithCompatibility`, `FillPlaceholder`) remains in the codebase. The `isPlaceholder` property and `"placeholder"` strategy values are intentionally retained as derived read-model contracts — they describe the demand-vs-assignment distinction at the frontend consumption layer, not legacy migration artifacts.
+No legacy _compatibility_ naming (e.g. `compatibilityId`, `AllocationFacade*`, `WithCompatibility`, `FillPlaceholder`) remains in the codebase. The `isPlaceholder` property and `"placeholder"` strategy values are intentionally retained as derived read-model contracts — they describe the demand-vs-assignment distinction at the frontend consumption layer, not legacy migration artifacts.
 
 ## Parallel Workstream Note