grammar+walker: 3j — shared insert/update/delete entry words (ADR-0033 §2 / Amendments 1 & 3)

Wire `insert`/`update`/`delete` as shared DSL/SQL entry words through the
category-grouped dispatcher (ADR-0033 Amendment 1): the Advanced SQL nodes
move off the dev words (`sqlinsert`/`sql_update`/`sql_delete`) to the real
keywords, registered alongside the Simple DSL nodes. Remove the dev-word
scaffold; collapse build_sql_{insert,update,delete} to source.trim();
de-duplicate the two REGISTRY entry-word listing sites.

Dispatch model (ADR-0033 Amendment 3, written this round):
- A command is the mode-rooted grammar-path outcome; identity is intrinsic.
  Advanced mode tries SQL first, falling back to the Simple DSL command when
  no SQL branch matches a token (`delete … --all-rows` falls back;
  `update … --all-rows` does not — the SET expression absorbs it, harmless
  since the engine treats `--all-rows` as a comment).
- Simple mode commits the DSL candidate for a shared word, surfacing the real
  DSL error; bare "this is SQL" is reserved for SQL-only entry words
  (`select`/`with`). A content rejection on the SQL candidate (internal
  table) is committed, never masked by the DSL fallback.

Combined DSL-error + advanced-SQL pointer (ADR-0033 Amendment 3): a Simple-mode
definite DSL error that would run as SQL in advanced mode gains the
`advanced_mode.also_valid_sql` suffix — in the live hint (ambient_hint_in_mode)
and on submit (dispatch_dsl), via the shared advanced_alternative_note — so the
actionable DSL fix and the mode pointer coexist (submit covers constructs that
surface only on submit, e.g. `delete … returning`).

Internal-table rejection symmetrised (/runda finding B, ADR-0030 §6): the DSL
data-command target slots (insert/update/delete/show data/show table) gained
reject_internal_table, so `__rdbms_*` tables are refused in Simple mode too —
previously only the advanced SQL grammar rejected them.

Mode-awareness: classify_input_with_schema_in_mode and
invalid_ident_at_cursor_in_mode stop leaking the advanced SQL view into
simple-mode hints for shared words.

Tests: dev-word inputs migrated to the real words (advanced); DSL grammar /
completion / phase-D / db tests parse in Simple mode (the DSL surface); replay
keeps its advanced-mode model (one stale assertion fixed); dispatcher routing,
combined-pointer, and internal-table tests added. Suite 1626 pass / 0 fail /
1 ignored; clippy --all-targets -D warnings clean.

Defer M4 (execution-time mode side-channel; tracked in requirements.md) to its
own ADR.

docs/requirements.md

@@ -120,6 +120,19 @@ handoff-14 cleanup; 449 after B2/C2.)
   one-shot advanced escape (with the prompt label updated). The
   `mode simple` / `mode advanced` command switches modes
   persistently.
+- [~] **M4** Execution-time mode side-channel — deferred, awaiting
+  its own ADR (ADR-0033 Amendment 3). Every command should know, at
+  execution time, which of three modes it ran under — `simple`,
+  `advanced`, or `advanced-one-shot` (the `:` escape) — so execution
+  can adjust *output* without changing command *identity* (e.g. a
+  simple-mode `create table` echoing the generated SQL when run in
+  advanced mode, silent in simple). Today only the *rendering*
+  side-channel exists (`OutputLine.mode_at_submission`); the `Mode`
+  enum is two-way, the one-shot distinction is collapsed at
+  submission, and neither `Action::ExecuteDsl` nor the worker carries
+  any mode. The work widens `Mode` to three-way and threads it
+  through the `Action` → worker interface. Not required for Phase 3
+  dispatch correctness; tracked here so it is not lost.
 
 ## App-level commands (per ADR-0003)