perf(invoices): lazy-load pdf-lib + swissqrbill, -516 KB on route

/(app)/invoices/[id] route bundle drops from **534 KB → 18.6 KB** by
moving PDF rendering behind dynamic imports.

Changes:
  - views/DetailView.svelte: `await import('../pdf/renderer')` inside
    renderPdf() + downloadPdf(), cached in a module-local ref.
  - components/SendModal.svelte: same for openAndDownload().
  - pdf/scor.ts (new): generateSCORReference extracted so the
    invoices store can derive a reference string without pulling
    swissqrbill/svg + pdf-lib into the list-view bundle.
  - pdf/qr-bill.ts: re-exports generateSCORReference from scor.ts
    for backward compatibility.
  - stores/invoices.svelte.ts: imports from ../pdf/scor (light) instead
    of ../pdf/qr-bill (heavy).
  - index.ts: drop re-export of the PDF renderer from the module
    barrel so `import ... from '$lib/modules/invoices'` never drags
    pdf-lib in.

The heavy chunk (pdf-lib + swissqrbill, ~576 KB) now only loads when
a user actually opens an invoice detail — list views, create flow, and
all other routes stay lean.

20/20 qr-bill tests pass; svelte-check clean.

Bonus: scripts/audit-icon-usage.mjs (+ pnpm run audit:icon-usage)
audits @mana/shared-icons imports. Reveals 204 distinct icons across
the codebase, 199 of them at default weight but paying for all 6
Phosphor weights. Biggest offender: app-registry/apps.ts with 69
static icon imports accounting for ~290 KB of the shared 466 KB icon
chunk. Migration path for that is documented in
docs/optimizable/bundle-analysis.md §2 — next session's work.

docs/optimizable/bundle-analysis.md also updated with the root (app)
layout (260 KB) investigation notes (start/stop lifecycle hooks to
defer via idleCallback).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/optimizable/bundle-analysis.md

@@ -45,23 +45,57 @@ Routes loaded per navigation (not eagerly):
 
 ## Priority improvements
 
-1. **`/invoices/[id]` code-split** — 534 KB is large. `swissqrbill`
-   and `pdf-lib` are probably both eagerly imported. Wrap the PDF/QR
-   generation path with `await import('swissqrbill')` so the route
-   bundle drops to ~150 KB for the list/display case. Real win for
-   Swiss-bill users on 3G / slow laptops.
+### 1. `/invoices/[id]` code-split — ✅ **SHIPPED 2026-04-22**
 
-2. **`@mana/shared-icons` chunking** — 317 + 149 KB of Phosphor SVG
-   paths across two chunks. Phosphor doesn't tree-shake well because
-   its icons are named exports of a single module. Either:
-   - migrate to tree-shakable per-icon imports, OR
-   - lazy-load rarely-used icons in the module that imports them
-   instead of the shared chunk.
+**Before:** 534 KB route bundle. **After:** 18.6 KB.
 
-3. **Root `(app)` layout (260 KB)** — on the high side for "just the
-   shell". Investigate whether any module-specific stores / AI pipeline
-   bits are leaking into the shared layout when they could be
-   route-scoped.
+`DetailView.svelte` + `SendModal.svelte` now import `./pdf/renderer`
+dynamically (`await import(...)`) so pdf-lib + swissqrbill/svg (~576 KB
+combined) move into a separate chunk that only loads when the user
+actually opens an invoice detail. Also split `generateSCORReference`
+into its own `./pdf/scor.ts` so the invoices store can compute a
+reference on create without pulling the heavy renderer graph.
+
+### 2. `@mana/shared-icons` — **OPEN**
+
+466 KB of Phosphor SVG paths across 2 chunks. Root cause from
+`audit:icon-usage` report (2026-04-22):
+
+- **204 distinct icons** imported across the codebase.
+- **199 use the default "regular" weight** — but Phosphor ships all
+  6 weights per icon regardless.
+- Single worst offender: `app-registry/apps.ts` imports **69 icons**
+  in one file (the module-name → icon-component map), pulled into the
+  shared layout chunk → 69 × 6 weights × ~0.7 KB ≈ 290 KB on every
+  cold load.
+
+**Migration paths** (pick one, sized to follow-up sessions):
+
+1. Rewrite `app-registry/apps.ts` so each module's icon is a string
+   name, with a lazy `getIconComponent(name)` helper backed by
+   per-path dynamic imports (`() => import('phosphor-svelte/House')`).
+   Saves ~290 KB from the initial layout chunk. Biggest single win.
+2. Drop `export * from 'phosphor-svelte'` in
+   `packages/shared-icons/src/index.ts` and re-export only the 204
+   icons actually used. Defends against future barrel-broadening.
+3. Longest-term: build a custom icon set that only ships the weights
+   actually used (most icons only need "regular").
+
+Run `pnpm run audit:icon-usage --top 30` for the current inventory.
+
+### 3. Root `(app)` layout (260 KB) — **OPEN**
+
+`routes/(app)/+layout.svelte` statically imports ~15 start/stop
+lifecycle hooks (mission tick, server-iteration executor, event store,
+event bridge, streak tracker, goal tracker, byok init, tools init,
+articles-from-news migration, reminder scheduler, llm queue). Each
+pulls its own dependency graph into the shared layout chunk.
+
+**Recommended approach:** wrap the non-critical ones in `queueMicrotask`
+or `requestIdleCallback`-deferred dynamic imports — the layout finishes
+hydrating, then the heavy lifecycle code streams in. The one-shot
+`runArticlesFromNewsMigration` in particular is a prime candidate since
+it's executed only once per user per session.
 
 ## What's already good