refactor(apps)!: delete web-tanstack demo app

Veect retrofit (ADR-027): the product is a hosted SaaS built on
web-next; apps/web-tanstack existed only as template demo surface for
the TanStack Start framework path. This slice removes the app and all
wiring that referenced it:

- turbo.json globalEnv: WEB_TANSTACK_SENTRY_DSN,
  VITE_WEB_TANSTACK_SENTRY_DSN, VITE_GIT_COMMIT_SHA,
  SENTRY_PROJECT_WEB_TANSTACK
- .env.example: the same four DSN/release vars
- generator e2e fixtures that stripped deps from the app's package.json
- coverage diff comment + test fixtures referencing apps/web-tanstack
- app-list entries in README, CLAUDE.md (port table, Sentry projects),
  AGENTS.md (tags, binder list, per-app docs), docs/glossary.md (App)
- pnpm-lock.yaml importer + orphaned transitive deps

Framework-support code in core packages stays: core-trpc's TanStack
provider, core-shared security/tanstack middleware, and the Sentry
react/node init adapters are generic TanStack support, not app wiring.
Prose in guides/ADRs/library traces is story 08 scope.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016j8z4VHjedXDTjEDNg7qHK

scripts/coverage/diff.mjs

@@ -71,7 +71,7 @@ const ALLOWED_GLOBS = [
   // Tooling packages that don't generate a vitest lcov (no @vitest/coverage-v8)
   /^packages\/core-testing\//,
   /^packages\/core-eslint\//,
-  // App packages (web-next, web-tanstack, cms) do not configure
+  // App packages (web-next, cms) do not configure
   // @vitest/coverage-v8, so their source files never appear in the merged lcov.
   /^apps\//,
   // core-shared Sentry client init files — explicitly excluded from per-package