Phase C scope decision: Diagnostic carries no class key, so the F1
diagnostic route would need a class field threaded through every
diagnostic site (broad change) for marginal value — tier-2 already
surfaces diagnostics and many duplicate the runtime error classes. Defer
the route + the ~33 diagnostic.* tier-3 blocks to issue #38. v1 ships
command-form hints + 9 runtime error-class hints (comprehensive for
those). Updates ADR-0053 D2/D6/Status/OOS + README.
The first exemplar (`add 1:n relationship`) showed per-node keying is
too coarse for multi-form commands, so revise the mechanism to per-form.
- CommandNode `hint_id: Option<&str>` -> `hint_ids: &[&str]` (mirrors
usage_ids); hint_key_for_input_in_mode reuses a factored-out
pick_form_key (shared digit/m:n/suffix form disambiguation with
usage_key_for_input_in_mode)
- wire INSERT + ADD (all four forms) with hint_ids
- author the three approved exemplars: hint.cmd.insert,
hint.cmd.add_relationship, hint.err.foreign_key.child_side
(what/example/concept) + keys.rs registration
- revise ADR-0053 D3 to per-form; record clause-concept hints as a
deferred extension (issue #37); update README + plan
- +5 tests; 2488 pass / 1 ignored, clippy clean
Settles the `hint` slot ADR-0003 left pending; closes the last open
piece of A1. Two surfaces (F1 → live-input hint; `hint` command →
last-error expansion), no topic arg, and a new tier-3 teaching corpus
keyed on a new CommandNode `hint_id` so advanced-SQL forms get distinct
mode-correct content. Comprehensive content for v1, authored
exemplars-first. Refines ADR-0003; references ADR-0019/0021/0022/0049/
0051. Files #36 for the parallel help-side gap.
claude@clouddev1