Merge nucleic/hazy-velvet-urchin-kzfr into dev

NUCLEIC_FORK.md

@@ -11,6 +11,7 @@ Every fork change is marked with a `// nash:` comment. Current patches:
 | --- | --- |
 | `brush-shell/src/productinfo.rs` | `PRODUCT_NAME` → `nash`; display string identifies the fork |
 | `brush-shell/src/args.rs` | usage/version strings rebranded |
+| `brush-core/src/prompt.rs` | `\$` (`PromptPiece::DollarOrPound`) renders the atom sign `⚛` (U+269B) for non-root instead of `$`; root still shows `#` |
 | `brush-core/src/expansion.rs` | corpus divergence D1: added `ExpansionPiece::LiteralText` — literal unquoted text is never field-split (bash splits only expansion results) but keeps glob characters active. Parameter-expansion substitutions (`${v:-word}` etc.) convert back to splittable at the expansion boundary; `ExpanderOptions.field_split_literal_text` lets data-string callers opt in. Upstream candidate. |
 | `brush-core/src/completion.rs` | `compgen -W` word list opts into `field_split_literal_text` (the -W string is data) |
 | `brush-shell/tests/cases/compat/ifs.yaml` | removed `known_failure` from 3 IFS tests the D1 fix repairs |

brush-core/src/prompt.rs

@@ -87,7 +87,8 @@ fn format_prompt_piece(
             if users::is_root() {
                 "#".to_owned()
             } else {
-                "$".to_owned()
+                // nash: the interactive shell symbol is the atom sign (U+269B) rather than `$`.
+                "\u{269B}".to_owned()
             }
         }
         // NOTE: We mimic bash and convert \[ into \001, a.k.a. RL_PROMPT_START_IGNORE.