style: remove em/en dashes repo-wide, add CLAUDE.md rule against them (#890)

Em dashes (—) and en dashes (–) had spread across comments, docs, tests,
and a few UI strings, reading as AI-generated boilerplate rather than
house style. Replaced each with punctuation matching its context: colon
for explanatory clauses, comma for asides, plain hyphen for numeric/legal
ranges (e.g. "21-23§"), "to"/"till" for date ranges, parentheses for
paired-dash asides. messages/en.json and messages/sv.json were fixed by
hand together to keep sv/en in sync.

Left untouched where the dash is the functional subject rather than
decorative punctuation: date-range-parser.ts's separator regex,
charset-repair.ts's CP1252 byte-mapping table (and its test), the SIE
encoding mojibake docs, generic-csv.ts's minus-sign normalizer, the
agent system-prompt files that already instruct against em dashes, and
a golden iXBRL test fixture compared byte-for-byte.

Also fixes two bugs surfaced along the way: an off-by-one in
ApiKeysPanel's scope-label split (a leftover from an earlier partial
pass), and a charset-repair test that had lost the literal en-dash it
exists to verify.

Regenerated the agent atom seed migration (skills:generate) since 27
SKILL.md files changed. Added a CLAUDE.md rule against em/en dashes,
with an explicit carve-out for the functional-dash cases above.

Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>

app/api/articles/[id]/route.ts

@@ -66,7 +66,7 @@ export const PATCH = withRouteContext(
       }
     }
 
-    // Sparse update — only the fields the caller actually sent.
+    // Sparse update: only the fields the caller actually sent.
     const updateData: Record<string, unknown> = {}
     for (const key of [
       'name', 'name_en', 'type', 'unit', 'price_excl_vat', 'vat_rate',

app/api/articles/__tests__/route.test.ts

@@ -62,7 +62,7 @@ describe('GET/POST /api/articles', () => {
 
   it('POST rejects a 3xxx revenue_account unknown to both chart and BAS catalogue', async () => {
     // Non-3xxx numbers are already stopped by the Zod schema; the route-level
-    // 'invalid' branch covers 3xxx numbers that exist nowhere — no chart row
+    // 'invalid' branch covers 3xxx numbers that exist nowhere, no chart row
     // and not in the BAS reference (3041 is not a BAS 2026 account).
     enqueue({ data: null })
 

app/api/articles/route.ts

@@ -12,7 +12,7 @@ import type { Article } from '@/types'
 
 ensureInitialized()
 
-// GET /api/articles — list the active company's articles. `?include_inactive=1`
+// GET /api/articles: list the active company's articles. `?include_inactive=1`
 // returns soft-deactivated ones too (the register page can show an archive view).
 export const GET = withRouteContext(
   'article.list',