docs(standards): fix the block's H1 and the false default-reviewer claim (backend#1602)

[LukasWodka]

Summary

Both fixes @saqlainsyed007 raised on the sync PRs (backend#1611, averaging-service#308). He correctly identified both as source-side: the synced block must never be hand-edited in a consuming repo, so fixing it in the 18 open sync PRs would have been the wrong move.

1. Second H1 (markdownlint MD025). The block opened with # tracebloc engineering standards (org-wide) while every consuming CLAUDE.md already has # CLAUDE.md as its sole title. Two H1s in one document read as two document titles and break the outline. Every heading is demoted one level, so the standards nest as a section under the host doc's title.

2. The default-reviewer claim was false. The block asserted "Each repo's CLAUDE.md names its default reviewer" — and no repo does. Worse, it contradicts the org's actual model (RFC-BACKEND-0008 D31: author-picks-reviewer, no automation assigns anyone). Its own closing rule says a change making a CLAUDE.md statement false must be corrected in the same PR, so the block was self-violating.

Rather than add a fabricated default reviewer to 18 repos, the line now describes what we really do:

You pick the reviewer: whoever knows the code best. There is no per-repo default, and no automation assigns one — branch protection just refuses to merge without a review.

Test plan

• scripts/tests/standards-sync-selftest.py — 20 checks, 0 failed
• Once this lands, standards-sync.py --create-prs refreshes all 18 open sync PRs against the corrected canon. They are DRIFTED until then, which is the expected state the script's own docstring describes.

🤖 Generated with Claude Code

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Note

Low Risk
Documentation-only change to the canonical standards snippet; no runtime, auth, or deployment behavior is affected.

Overview
Updates the canonicalorg-standards.md block that syncs into every repo’s CLAUDE.md, so consuming docs stay valid and accurate after the next standards-sync run.

Heading structure: The block title and section headings are demoted one level (# → ##, ## → ###) so the synced content nests under each host file’s existing # CLAUDE.md title and avoids a second top-level H1 (markdownlint MD025).

Reviewer policy: The Branches & PRs bullet no longer says each repo’s CLAUDE.md names a default reviewer. It now states that the author picks whoever knows the code best, there is no per-repo default and no automation assigns a reviewer, and branch protection still requires a review before merge.

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