Build: Reduce Tailwind sourcemap and Node DEP0155 warnings

[mjkatgithub]

Planning

• Milestone: Phase 3 (or Backlog if deferred)
• Priority: P3
• Size: S
• Estimate: 2 SP

Goal

Reduce non-fatal build noise during npm run build so CI and local
logs stay actionable. Follow-up to #62
(bundle splitting); does not change runtime behavior.

Background

After #62, production builds succeed but still emit:

1. Tailwind Vite plugin (×2, SSR build):

   [plugin @tailwindcss/vite:generate:build] Sourcemap is likely to be incorrect …
   

   Comes via @nuxt/ui / Tailwind 4 — affects CSS sourcemap quality in build,
   not bundle splitting.

2. Node.js DEP0155 (multiple lines during Nitro):

   DeprecationWarning: … trailing slash pattern mapping "./" in the "exports" field …
   

   Transitive deps: @iconify/utils, @vue/shared, @vueuse/core,
   reka-ui nested @vueuse — upstream package.json exports, not Decentra code.

Documented as expected noise in docs/build-bundling.md;
this issue tracks real fixes where possible.

Scope

• Reproduce and capture full warning list on Node 20 (CI) and local Node 22.
• Tailwind: try fixes in order — dependency bump (@nuxt/ui / @tailwindcss/vite),
  vite.build.sourcemap / CSS sourcemap options; document if upstream-only.
• DEP0155: check for patched versions of affected packages; avoid
  NODE_OPTIONS=--no-deprecation unless documented as last resort for CI only.
• Extend docs/build-bundling.md with "Known build warnings" + resolution status.
• If nothing fixable without major upgrades: close with documented rationale
  and links to upstream issues.

Nicht im Scope

• Vite ">500 kB chunk" warning for matrix-js-sdk (expected; see Build: Bundle-Analyse und Chunk-Splitting (matrix-js-sdk) #62).
• Parallel-build ENOENT on .cache/nuxt (operational: one build at a time).
• Runtime performance (Perf: Chat-Laufzeit — scoped computeds und Sidebar-Updates #103).

Branch

feature/build-warning-cleanup

Acceptance Criteria

• npm run build log has fewer warnings or docs explain each remaining
  warning with upstream link / "won't fix until dependency X".
• No regression: npm run build, npm run test:e2e:smoke green.
• Suppression flags (if any) are minimal and documented in docs/build-bundling.md.

Test Checklist

• npm run build on clean tree (no parallel builds).
• Compare warning count before/after (paste in PR).
• npm run test:e2e:smoke unchanged.

Related

• Build: Bundle-Analyse und Chunk-Splitting (matrix-js-sdk) #62 — bundle analysis / manualChunks (done)
• Docs: Project map for agents and developers (follow-up #63) #116 — project architecture docs (may cross-link build section)

Notes

Spawned from #62 PR discussion: warnings are cosmetic but clutter local/CI output.