Closes P2 todo "CLI human-mode diagnostic surface for
WorkspaceLoadError" surfaced by ct.1.8 tester (2026-05-11).
Pre-iter, non-JSON `ail check` (+8 sibling subcommands) propagated
loader errors via anyhow's Display, producing
`Error: <message>` without the bracketed `[code]` prefix the JSON
path emits.
Fix: new private helper `load_workspace_human(path)` in
crates/ail/src/main.rs that wraps ailang_surface::load_workspace,
threads any WorkspaceLoadError through workspace_error_to_diagnostic,
formats the resulting Diagnostic into a single stderr line
`error: [<code>] <def>: <message>`, and exits non-zero. Pure I/O
errors still propagate as anyhow errors.
Nine call sites swapped to the helper (check non-JSON arm, build,
run, emit-ir, prose, describe, deps, diff, manifest). The JSON arm
of `ail check` keeps its explicit `match` — different output
contract (structured stdout array).
The BareCrossModuleTypeRef Diagnostic message gained the existing
migration-command hint ("Run `ail migrate-canonical-types` to fix
legacy fixtures.") so the ct.1.8 actionable-hint test stays green.
The hint previously rode on WorkspaceLoadError's thiserror Display;
making workspace_error_to_diagnostic the single source for both
JSON and human paths required moving it into the Diagnostic body.
RED test crates/ail/tests/cli_diag_human_workspace_load_error.rs
pins the bracketed-code surface on a missing-import workspace
(tempdir-based fixture; no committed corpus addition).
cargo test --workspace: 565/0/3. clippy + doc: zero warnings.
Roadmap entry struck.
Brummel
f08ba2bb36