chore: initialize EverOS 1.0.0

md-first memory extraction framework for AI agents.

Markdown is the single source of truth; SQLite holds state and LanceDB
provides the rebuildable vector + BM25 + scalar index. The codebase follows
a single-direction DDD layering (entrypoints -> service -> memory -> infra,
with component / core / config cross-cutting) enforced by import-linter.

Engineering surface:
- Coding conventions in .claude/rules/ (path-scoped) and workflows in
  .claude/skills/ (/commit, /new-branch, /pr).
- GitHub Actions CI runs make lint + test + integration; pre-commit mirrors
  the gates locally (ruff, hygiene hooks, gitlint commit-msg).
- Commit messages follow Conventional Commits, enforced by gitlint.
- make lint also enforces datetime two-zone discipline and OpenAPI drift.

docs/index.md

@@ -0,0 +1,63 @@
+# EverOS Documentation
+
+Documentation for [EverOS](../README.md) — md-first memory extraction
+framework. Organised by [Diátaxis](https://diataxis.fr/) — what kind of
+question you have determines which section to read.
+
+## Reference
+
+Technical reference: contracts, commands, schemas — read these when you
+already know what you want to do and need to know exactly how.
+
+| Doc | Purpose |
+|---|---|
+| [api.md](api.md) | HTTP API v1 reference — endpoints, request / response, error contracts |
+| [cli.md](cli.md) | `everos` CLI subcommands + env var conventions |
+| [storage_layout.md](storage_layout.md) | Memory-root tree + frontmatter chassis + EntryId encoding |
+| [prompt_slots.md](prompt_slots.md) | YamlConfigLoader + three-layer prompt override |
+
+## Explanation
+
+Design decisions and architectural concepts — read these to understand
+why the system is shaped the way it is.
+
+| Doc | Purpose |
+|---|---|
+| [overview.md](overview.md) | Project vision, scope, design philosophy |
+| [how-memory-works.md](how-memory-works.md) | Storage stack + on-disk paths + write→index→read pipeline + consistency |
+| [architecture.md](architecture.md) | DDD layered architecture + dependency rules |
+| [datetime.md](datetime.md) | Two-zone discipline — UTC at storage, display tz at boundaries |
+
+## How-to
+
+Task-driven operational guides — read these when you need to do a
+specific thing (drain a queue, recover from a stuck row, etc.).
+
+| Doc | Purpose |
+|---|---|
+| [cascade_runbook.md](cascade_runbook.md) | Cascade subsystem ops — drain queue, recover stuck rows |
+
+## Engineering / Internal
+
+For maintainers and contributors working on the framework itself,
+not for using it.
+
+| Doc | Purpose |
+|---|---|
+| [engineering.md](engineering.md) | Engineering & dev-efficiency infrastructure (CI / tooling / Claude Code) |
+
+## See also
+
+Top-level project files live next to the repo root:
+
+- [README.md](../README.md) — quick start & feature overview
+- [QUICKSTART.md](../QUICKSTART.md) — 5-minute walkthrough (install → service → search)
+- [CONTRIBUTING.md](../CONTRIBUTING.md) — how to contribute (issue-only model)
+- [CHANGELOG.md](../CHANGELOG.md) — release notes
+- [SECURITY.md](../SECURITY.md) — security policy & private vulnerability reporting
+- [CITATION.md](../CITATION.md) — academic citation info
+- [ACKNOWLEDGMENTS.md](../ACKNOWLEDGMENTS.md) — third-party acknowledgments
+
+Coding conventions and slash command workflows are auto-loaded by
+Claude Code from [.claude/rules/](../.claude/rules/) and
+[.claude/skills/](../.claude/skills/).