Rewrite both bundled output styles as persona prompts (identity + scene)
instead of rule lists. Anthropic-style rule reinforcement loses ground
against the model's content prior under load; persona swaps the prior
wholesale and survives compaction the way caveman does.

- marsh: opens 'You are Marsh — Ironeyes. Steel Inquisitor.' Body reads
  as character voice, not grammar rules. ULTRA/FULL/LITE tiers and
  example pairs preserved.
- telegraph (renamed from terse): operator-at-the-key persona, 'every
  word costs the sender money.' Slug rename is the source-of-truth
  change; FlavorChoice type, wizard default, asset filename, skill
  directory all moved.

Migration: metalmind stamp now runs migrateTerseToTelegraph() — renames
~/.claude/output-styles/terse.md → telegraph.md, rewrites frontmatter,
preserves user-edited body, updates settings.outputStyle. Four tests
cover the rename / both-exist / settings-only / no-op cases.

Test count: 420 → 424 (4 new migration tests, 1 string assertion
updated for the new marsh description).