fieldtest: milestone-research-artifacts corpus (GREEN) + Aura.toml data-key doc fix (F7)

MILESTONE VERDICT: GREEN — the whole span (0106-0109) holds end to
end as one continuous consumer scenario: authored from a bare {} via
introspection alone, every ref resolved from the public surface, three
validation tiers, run by content id over two real instruments through
the full v2 pipeline, realization recorded (selection/survivors/
bootstrap/generalizations/trace_name), traces on disk and charted,
read back via campaign runs, byte-identical re-runs (C1), refusals
precise. 0 bugs, 0 frictions, 0 spec gaps; 2 doc-gaps.

F7 fixed in this commit (the docs claimed an archive-root path without
naming the key; a guessed [paths] archive silently no-ops): project-
layout and the glossary Aura.toml entry now name [paths] data, and the
aura new template advertises the commented-out key. F8 (op-script
grammar not CLI-discoverable) filed as #208, sibling of the #197 docs
half — one docwriter pass once desired.

The milestone-close gate evidence is this corpus; the formal milestone
close and the push remain user-reserved.

refs #189

docs/project-layout.md

@@ -30,9 +30,10 @@ A project is always a Rust program built on the engine.
 
 ```
 ger40-lab/                 # your research project — a separate Rust crate (cdylib)
-├── Aura.toml              # STATIC context only, paths only: the runs dir (all
-│                          # the scaffold emits today), plus a data archive root
-│                          # once real data enters; no logic — instrument
+├── Aura.toml              # STATIC context only, paths only: `[paths] runs`
+│                          # (the runs dir) and `[paths] data` (the archive
+│                          # root; defaults to the built-in Pepperstone path
+│                          # when unset); no logic — instrument
 │                          # geometry is the recorded sidecar (C15), never
 │                          # authored here
 ├── Cargo.toml             # cdylib; depends on aura-core/aura-std (+ shared node crates);