chore: remove em dashes throughout repo

[soleil-colza]

Summary

Em dashes (U+2014) are banned from any text that ships in the repo (committed source, runtime strings, docs, READMEs, code comments). This PR catches up the existing content. 238 occurrences across 72 files swapped for grammatically appropriate punctuation.

Replacement strategy

• — connector (where the connector is so / but / and / or): replaced with , connector (comma).
• Plain X — Y (introducing an explanation, list, or quote): replaced with X: Y (colon).
• A few cases that would have produced double colons (Anonymous id: <id> — Arkor Cloud uses this id...) were rephrased with a period or wrapped in parentheses.
• JSX/UI placeholders like loss=${loss ?? \"—\"} swapped for a single hyphen.

Coordination with PR #108

Both this PR and #108 touch packages/cli-internal/src/templates.ts and packages/create-arkor/README.md. #108 removes a couple of paragraphs (the npm-vs-binary parenthetical and the npx arkor login example); this PR rewrites em dashes in the same files. Whichever lands second resolves the conflict trivially (take #108's deletions, then re-apply em-dash fixes to the surviving lines).

Test plan

• pnpm typecheck passes
• All unit tests pass except for one pre-existing GPG-signing test in packages/cli-internal/src/git.test.ts that already fails on main (unrelated to em dashes; depends on local GPG / git config)
• SKIP_E2E_INSTALL=1 pnpm --filter @arkor/e2e-cli test passes (38 tests)
• mint broken-links clean
• grep -rc \"—\" --include=\"*.{md,mdx,ts,tsx,mjs,js}\" returns zero in non-build files