feat(types)!: drop the blob column type (ADR-0005 Amendment 2)

blob was a dead-end: declarable but never fillable (no literal in either
mode, seed-unsupported), so a blob column could only ever hold NULL. Remove
Type::Blob + Value/CellValue::Blob + the base64 CSV path + the grammar slot
+ completion/render/type-change/seed handling + the binder refusal (whose
message also carried a user-facing "DSL" copy-rule bug). The vocabulary is
now nine types; base64 stays (clipboard OSC-52).

Backward compat is the ADR-0015 migration framework's first real use: a
v1->v2 format bump (CURRENT_SCHEMA_VERSION across serializer/parser/skeleton)
with a migrator that rewrites `type: blob` -> `type: text`, and a forced .db
rebuild from the migrated text when a blob column was actually converted
(the stale .db keeps a STRICT BLOB engine column). Conversion to text is
non-destructive and CSV-free. Covered by a full-stack integration test and a
Tier-4 PTY test that opens a real legacy v1-blob project.

Also sweeps the nine-type vocabulary through CLAUDE.md, requirements.md, the
website (type reference, seed doc, highlight grammar), and the ADR-0030/0033/
0035 cross-references; CHANGELOG Removed entry; handoff-79.

BREAKING CHANGE: the `blob` column type is removed. Existing projects that
declared a blob column are migrated on first open (the column becomes text;
the original project.yaml is kept as a .v1.bak).

src/dsl/grammar/sql_create_table.rs

@@ -567,7 +567,7 @@ mod tests {
     fn standard_sql_type_aliases() {
         good("table t (a integer, b varchar, c boolean, d timestamp)");
         good("table t (e bigint, f smallint, g char, h numeric)");
-        good("table t (i binary, j varbinary, k float)");
+        good("table t (k float)");
     }
 
     #[test]
@@ -734,7 +734,7 @@ mod builder_tests {
     fn standard_sql_aliases_map_to_playground_types() {
         let (_, cols, _, _) = sct(
             "create table t (a bigint, b varchar, c boolean, d timestamp, \
-             e numeric, f float, g binary)",
+             e numeric, f float)",
         );
         assert_eq!(
             cols,
@@ -745,7 +745,6 @@ mod builder_tests {
                 ("d".to_string(), Type::DateTime),
                 ("e".to_string(), Type::Decimal),
                 ("f".to_string(), Type::Real),
-                ("g".to_string(), Type::Blob),
             ]
         );
     }