README status line: sections (0.7.1)

[llima]

Summary

• Version bumped to 0.7.1. Merging publishes craftar@0.7.1 to npm after approval in the npm environment. This is a README-only release, so the npm page shows the current status line.
• The README status line (line 5) now names sections, which shipped in 0.7.0:
  • client-specific blocks in ingredient bodies, marked <!-- craftar:section <name> --> … <!-- /craftar:section -->;
  • overridden by a profile's sections and a workspace's overrides.sections;
  • each client's content is inferred by import;
  • a Forge that uses sections declares schema: 2.
• craftar.dev checks its claims against this line; it already describes sections (Site parity with craftar-cli 0.7.0: sections craftar-cli-site#9).

Test plan

• npm run typecheck: pass. npm run build: pass. craftar --version prints 0.7.1.
• npm test (before the bump): 28 files passed, 1 skipped; 676 passed, 5 skipped. Oracle skipped (no fixture); there is no code change.
• CI green on ubuntu and windows, Node 22 and 24.
• node-cli-reviewer and docs-author reviewed the change: both clean, with one optional wording nit left as is.