authvault 0.1.0

# Merge Prep Summary — `integration/consolidate`

## What this consolidates

- **Security & dependency hardening** — patchable CVE bumps in dependencies; expanded `SECURITY.md` with supported-versions table; hardened `.gitignore` to exclude build artifacts, `*.bak`, and coverage output.
- **Developer experience & repo hygiene** — added detailed `CONTRIBUTING.md` guidelines; normalized root `.editorconfig`; fixed `Cargo.toml` workspace detection by adding `[workspace]`; hardened `.gitignore` across two chore branches.
- **Testing & traceability** — added integration test for `Session::is_valid`; added domain unit test for `Session::revoke`; added unit test for `User::has_role` via role hierarchy (FR-AUTHVAULT-151); introduced traceability matrix skeleton and populated it for top 5 features.
- **Documentation** — expanded `SECURITY.md` and `CONTRIBUTING.md`; generated deterministic build-status doc for this branch.

## Tests added

| Test | Type | Scope |
|------|------|-------|
| `Session::is_valid` integration test | Integration | Session lifecycle |
| `Session::revoke` unit test | Unit | Domain / revocation |
| `User::has_role` via hierarchy | Unit | RBAC / FR-AUTHVAULT-151 |

## Traceability

- `TEST_COVERAGE_MATRIX.md` — skeleton created and mapped to top 5 features.
- `FR-AUTHVAULT-151` explicitly covered by `User::has_role` unit test.
- Deterministic build-verify generated `BUILD_STATUS.md` (commit `dba2ef1`).

## Build status

- `cargo check --workspace` — **0 errors** (verified deterministically on `integration/consolidate`).
- Workspace fix (`[workspace]` in `Cargo.toml`) resolves tooling detection issues without breaking existing builds.

## Merge risk

**Low** — all changes are additive (docs, tests, chore, patchable CVE bumps). No breaking API changes. Merge conflicts were resolved preferring incoming changes. Build is clean and test coverage has increased.