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/agent/memory/[id]/route.ts

@@ -8,13 +8,13 @@ import { requireWritePermission } from '@/lib/auth/require-write'
 // Mutate a single memory entry. Powers the list/edit/pin/dismiss affordances
 // on /settings/agent-memory (plan §11).
 //
-//   content    — edit the durable text (kind never changes; that would
+//   content: edit the durable text (kind never changes; that would
 //                muddle the audit lineage). Append-only is preserved by
 //                superseded_by chains when an upstream caller wants it; the
 //                transparency UI is allowed to overwrite in place because
 //                the row's `updated_at` already documents the edit.
-//   is_pinned  — boost into the top-N prompt block regardless of score.
-//   is_active  — false = dismiss (removes from ranking pool); true = restore.
+//   is_pinned: boost into the top-N prompt block regardless of score.
+//   is_active: false = dismiss (removes from ranking pool); true = restore.
 //
 // RLS scopes to user_company_ids(); we ALSO re-verify membership for the
 // row's company_id as defense in depth before mutating.

app/api/agent/memory/__tests__/route.test.ts

@@ -55,7 +55,7 @@ describe('GET /api/agent/memory', () => {
       {
         id: 'mem-1',
         kind: 'fact',
-        content: 'Räkenskapsår jan–dec',
+        content: 'Räkenskapsår jan-dec',
         source: 'composer',
         source_ref: null,
         relevance_score: 0.5,