Walker: node-attached HintMode via Node::Hinted (ADR-0024 §HintMode-per-node)

Replaces the hint resolver's signature-matching (does the expected set
contain all five literal forms? an Ident{NewName}?) with a grammar-
declared annotation. New Node::Hinted { mode, inner } wrapper; the
walker records the mode in WalkContext::pending_hint_mode on entry and
clears it on any successful match (cursor moved past the slot — this
also undoes the leak where a failed Hinted branch of a Choice would
otherwise strand a stale mode). The resolver reads pending_hint_mode
directly.

Value-literal fallback slots carry ProseOnly; NewName ident slots carry
ForceProse. hint_mode_at_input_inner now delegates to
hint_resolution_at_input — one resolution path, no duplicated logic.
No behaviour change; the typing-surface matrix guards it.

src/dsl/grammar/ddl.rs

@@ -14,9 +14,15 @@
 use crate::dsl::action::ReferentialAction;
 use crate::dsl::command::{ChangeColumnMode, ColumnSpec, Command, RelationshipSelector};
 use crate::dsl::grammar::{
-    CommandNode, IdentSource, Node, ValidationError, Word,
+    CommandNode, HintMode, IdentSource, Node, ValidationError, Word,
     shared::{REFERENTIAL_CLAUSES, TYPE_SLOT, TYPE_VALIDATOR},
 };
+
+/// `HintMode` annotation shared by every `NewName` ident slot:
+/// the user is inventing a name, so the hint panel forces the
+/// "Type a name [then …]" prose rather than offering schema
+/// candidates (ADR-0024 §HintMode-per-node).
+const NEW_NAME_HINT: HintMode = HintMode::ForceProse("hint.ambient_typing_name");
 use crate::dsl::types::Type;
 use crate::dsl::walker::outcome::{MatchedKind, MatchedPath};
 
@@ -24,7 +30,7 @@ use crate::dsl::walker::outcome::{MatchedKind, MatchedPath};
 // Building blocks
 // =================================================================
 
-const TABLE_NAME_NEW: Node = Node::Ident {
+const TABLE_NAME_NEW_IDENT: Node = Node::Ident {
     source: IdentSource::NewName,
     role: "table_name",
     validator: None,
@@ -33,6 +39,10 @@ const TABLE_NAME_NEW: Node = Node::Ident {
         writes_column: false,
         writes_user_listed_column: false,
 };
+const TABLE_NAME_NEW: Node = Node::Hinted {
+    mode: NEW_NAME_HINT,
+    inner: &TABLE_NAME_NEW_IDENT,
+};
 
 // `writes_table: true` so that the column-name slots that
 // follow the table name in `drop column` / `rename column` /
@@ -61,7 +71,7 @@ const COLUMN_NAME: Node = Node::Ident {
         writes_user_listed_column: false,
 };
 
-const COLUMN_NAME_NEW: Node = Node::Ident {
+const COLUMN_NAME_NEW_IDENT: Node = Node::Ident {
     source: IdentSource::NewName,
     role: "column_name",
     validator: None,
@@ -70,6 +80,10 @@ const COLUMN_NAME_NEW: Node = Node::Ident {
         writes_column: false,
         writes_user_listed_column: false,
 };
+const COLUMN_NAME_NEW: Node = Node::Hinted {
+    mode: NEW_NAME_HINT,
+    inner: &COLUMN_NAME_NEW_IDENT,
+};
 
 const RELATIONSHIP_NAME: Node = Node::Ident {
     source: IdentSource::Relationships,
@@ -81,7 +95,7 @@ const RELATIONSHIP_NAME: Node = Node::Ident {
         writes_user_listed_column: false,
 };
 
-const RELATIONSHIP_NAME_NEW: Node = Node::Ident {
+const RELATIONSHIP_NAME_NEW_IDENT: Node = Node::Ident {
     source: IdentSource::NewName,
     role: "relationship_name",
     validator: None,
@@ -90,6 +104,10 @@ const RELATIONSHIP_NAME_NEW: Node = Node::Ident {
         writes_column: false,
         writes_user_listed_column: false,
 };
+const RELATIONSHIP_NAME_NEW: Node = Node::Hinted {
+    mode: NEW_NAME_HINT,
+    inner: &RELATIONSHIP_NAME_NEW_IDENT,
+};
 
 // `[to]` and `[table]` connectives.
 const TO_OPT: Node = Node::Optional(&Node::Word(Word::keyword("to")));
@@ -308,6 +326,20 @@ const ADD_SHAPE: Node = Node::Choice(ADD_CHOICES);
 // rename_column — `rename column [in] [table] <T> : <col> to <new>`
 // =================================================================
 
+const NEW_COLUMN_NAME_IDENT: Node = Node::Ident {
+    source: IdentSource::NewName,
+    role: "new_column_name",
+    validator: None,
+    highlight_override: None,
+    writes_table: false,
+    writes_column: false,
+    writes_user_listed_column: false,
+};
+const NEW_COLUMN_NAME: Node = Node::Hinted {
+    mode: NEW_NAME_HINT,
+    inner: &NEW_COLUMN_NAME_IDENT,
+};
+
 const RENAME_COLUMN_NODES: &[Node] = &[
     Node::Word(Word::keyword("column")),
     IN_OPT,
@@ -316,15 +348,7 @@ const RENAME_COLUMN_NODES: &[Node] = &[
     Node::Punct(':'),
     COLUMN_NAME,
     Node::Word(Word::keyword("to")),
-    Node::Ident {
-        source: IdentSource::NewName,
-        role: "new_column_name",
-        validator: None,
-        highlight_override: None,
-        writes_table: false,
-        writes_column: false,
-        writes_user_listed_column: false,
-    },
+    NEW_COLUMN_NAME,
 ];
 const RENAME_COLUMN: Node = Node::Seq(RENAME_COLUMN_NODES);
 
@@ -650,16 +674,22 @@ pub static CHANGE: CommandNode = CommandNode {
 //                                          (Phase C)
 // =================================================================
 
+const COL_NAME_IDENT: Node = Node::Ident {
+    source: IdentSource::NewName,
+    role: "col_name",
+    validator: None,
+    highlight_override: None,
+    writes_table: false,
+    writes_column: false,
+    writes_user_listed_column: false,
+};
+const COL_NAME: Node = Node::Hinted {
+    mode: NEW_NAME_HINT,
+    inner: &COL_NAME_IDENT,
+};
+
 const COL_SPEC_NODES: &[Node] = &[
-    Node::Ident {
-        source: IdentSource::NewName,
-        role: "col_name",
-        validator: None,
-        highlight_override: None,
-        writes_table: false,
-        writes_column: false,
-        writes_user_listed_column: false,
-    },
+    COL_NAME,
     Node::Punct(':'),
     Node::Ident {
         source: IdentSource::Types,