feat(project): the project-as-crate load boundary (cycle 0102)

A research project is now a loadable external cdylib crate. Inside a
directory whose ancestry holds an Aura.toml, aura discovers the project
root cargo-style, locates the compiled dylib via cargo metadata (debug
default, --release opt-in), loads it load-and-hold, and refuses
mismatches before trusting anything: the AURA_PROJECT descriptor
(aura-core::project, #[repr(C)]) carries a C-ABI stamp prefix (rustc +
aura-core version, baked per consuming build by the new aura-core
build.rs) validated before any Rust-ABI field is read. The vocabulary
charter gates the merged resolution: project type ids are ::-namespaced
(std stays bare), duplicates refuse, and the enumerable type-id list
must agree with the resolver, so introspection can never silently omit
a project type.

All blueprint verbs resolve through the merged project + std vocabulary
via a per-invocation Env threaded through the dispatch chains;
registry, trace-store, and data paths anchor at the project runs root
(Aura.toml [paths], paths-only by design — instrument geometry stays
the recorded sidecar, C15). RunManifest gains the Tier-1 project
provenance field (namespace + dylib sha256 + best-effort commit),
stamped beside topology_hash on the blueprint-run paths; pre-0102
registry lines load unchanged. Default node names strip the namespace,
so :: never reaches the param-path address space.

Proven by the demo-project fixture (built by the e2e via cargo,
path-dep on this workspace): run twice bit-identical, provenance
recorded, introspection lists demo::* beside std, registry anchors at
the discovered root from a subdirectory; the badcharter fixture proves
the charter refusal through the real libloading path; a never-built
project refuses with a cargo-build hint. Outside a project every path
collapses to the previous literals — goldens and manifest pins
byte-identical.

Verification: cargo build --workspace clean; cargo test --workspace 862
passed / 0 failed (incl. 7 project_load e2e); clippy -D warnings clean
(one precedent-matching allow(too_many_arguments) on run_oos_blueprint,
whose arity the Env threading raised to 8); doc build unchanged.
Docs/ledger aligned: Aura.toml field lists are paths-only in
project-layout.md, glossary, C16/C17; new C13 realization note records
the per-invocation-reload reading and the load-and-hold one-shot scope
boundary.

New deps, per-case review (aura-cli leaf binary only, never the frozen
artifact): libloading, toml.

refs #180

crates/aura-cli/Cargo.toml

@@ -40,6 +40,8 @@ libc = "0.2"
 # SHA256 user-settled); lives in the research-side CLI, off the frozen engine
 # (invariant 8).
 sha2 = "0.10"
+libloading = "0.8"
+toml = "0.8"
 # clap: the vetted standard argument parser. Adopted (C16 per-case review) to
 # replace the hand-rolled argv parser + ten duplicated help surfaces with one
 # declarative source, giving scoped --help, --version, --flag=value, and