What

Create a Single Source of Truth (SSOT) documentation registry in each project's
docs/README.md, listing every document with its authoritative topic, status,
and location.

Why

With 54-85 documentation files per project, there is no central index showing
which document is the authoritative source for each topic. This leads to
duplicated or conflicting information across files. An SSOT registry provides a
machine-readable, human-navigable index that prevents documentation drift.

Where

How

Registry Format

Each docs/README.md should contain:

# Documentation Registry

> **SSOT**: This file is the single source of truth for the documentation index
> of {project_name}.

## Document Index

| # | doc_id | Topic | Authority Document | Section | Status |
|---|--------|-------|-------------------|---------|--------|
| 1 | THR-ARCH-001 | Thread Pool Architecture | [ARCHITECTURE.md](./ARCHITECTURE.md) | §2 | Released |
| 2 | THR-GUID-001 | Queue Selection Criteria | [QUEUE_SELECTION_GUIDE.md](./QUEUE_SELECTION_GUIDE.md) | — | Released |
| 3 | THR-PERF-001 | Performance Baselines | [BENCHMARKS.md](./BENCHMARKS.md) | §3 | Released |

SSOT Declaration Convention

Each authoritative document should include a declaration near its top:

> **SSOT**: This section is the single source of truth for {topic}.

Implementation Steps

1. Inventory all docs/ files per project (use existing frontmatter doc_ids from docs: Add YAML frontmatter to all docs/ markdown files #562)
2. Determine the authoritative topic for each document
3. Build the registry table in docs/README.md
4. Add SSOT declarations to each authoritative document
5. Verify no topic has multiple conflicting authority documents

Acceptance Criteria

• All 8 projects have an SSOT registry table in docs/README.md
• Each entry has doc_id, topic, file link, and status
• No duplicate authority topics within a project
• Key documents have SSOT declarations
• All file links are valid (no broken links)

Related

• Part of docs: Ecosystem documentation improvement — enterprise-level standardization #559 (Ecosystem documentation improvement)
• Depends on docs: Add YAML frontmatter to all docs/ markdown files #562 (YAML frontmatter — provides doc_id values)