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

crates/aura-cli/src/scaffold.rs

@@ -103,6 +103,7 @@ aura-core = { path = "__ENGINE__/crates/aura-core" }
 const AURA_TOML: &str = r#"# Static project context only (C17); paths only.
 [paths]
 runs = "runs"
+# data = "/path/to/archive"  # the recorded-data root; defaults to the built-in path
 "#;
 
 const GITIGNORE: &str = "/target\nCargo.lock\n/runs\n";