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/extensions/enable-banking/callback/__tests__/route.test.ts

@@ -1,6 +1,6 @@
 import { describe, it, expect, vi, beforeEach } from 'vitest'
 
-// Mock dependencies — factory must not reference outer variables
+// Mock dependencies: factory must not reference outer variables
 const mockCreateSession = vi.fn()
 const mockGetAccountBalance = vi.fn()
 vi.mock('@/extensions/general/enable-banking/lib/api-client', () => ({
@@ -70,7 +70,7 @@ describe('GET /api/extensions/enable-banking/callback', () => {
         // Find pending connection by oauth_state
         return mockChain({ data: { id: 'conn-1', user_id: 'user-1', company_id: 'company-1' }, error: null })
       }
-      // Update connection — capture the payload, then chain returns the
+      // Update connection: capture the payload, then chain returns the
       // updated row via .select().single() for the audit event emission.
       const chain: Record<string, unknown> = {}
       chain.update = vi.fn((payload: Record<string, unknown>) => {