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).

tests/it/sql_dml_e2e.rs

@@ -208,13 +208,12 @@ fn e2e_insert_select_cross_table_copies_rows_and_persists_both() {
 // ===============================================================
 
 #[test]
-fn e2e_multirow_insert_all_ten_types_roundtrips_and_returning_recovers_each_type() {
+fn e2e_multirow_insert_all_nine_types_roundtrips_and_returning_recovers_each_type() {
     let (project, db, _dir) = open_project_db();
     let rt = rt();
-    // serial PK + shortid auto-fill; the other eight columns are
-    // user-supplied. `blob` has no value-literal grammar yet
-    // (see src/dsl/value.rs), so it is inserted NULL — its *type*
-    // still round-trips through the RETURNING column-origin path.
+    // serial PK + shortid auto-fill; the other seven columns are
+    // user-supplied. Their *types* round-trip through the RETURNING
+    // column-origin path.
     create_cols(
         &db,
         &rt,
@@ -228,7 +227,6 @@ fn e2e_multirow_insert_all_ten_types_roundtrips_and_returning_recovers_each_type
             ("flag", Type::Bool),
             ("d", Type::Date),
             ("ts", Type::DateTime),
-            ("bl", Type::Blob),
             ("sid", Type::ShortId),
         ],
         &["ser"],
@@ -237,17 +235,17 @@ fn e2e_multirow_insert_all_ten_types_roundtrips_and_returning_recovers_each_type
     let result = run_insert(
         &db,
         &rt,
-        "insert into allten (txt, i, r, dec, flag, d, ts, bl) values \
-         ('hi', 42, 1.5, 9.50, true, '2026-05-23', '2026-05-23 10:00:00', null), \
-         ('yo', 7, 2.5, 3.25, false, '2025-01-01', '2025-01-01 00:00:00', null) \
-         returning ser, txt, i, r, dec, flag, d, ts, bl, sid",
+        "insert into allten (txt, i, r, dec, flag, d, ts) values \
+         ('hi', 42, 1.5, 9.50, true, '2026-05-23', '2026-05-23 10:00:00'), \
+         ('yo', 7, 2.5, 3.25, false, '2025-01-01', '2025-01-01 00:00:00') \
+         returning ser, txt, i, r, dec, flag, d, ts, sid",
     )
     .expect("multi-row INSERT … RETURNING runs");
 
     assert_eq!(result.rows_affected, 2, "two rows inserted");
     assert_eq!(result.data.rows.len(), 2, "RETURNING yields both rows");
 
-    // Every one of the ten playground types is recovered via the
+    // Every one of the nine playground types is recovered via the
     // RETURNING column-origin path (matrix R5).
     assert_eq!(
         result.data.column_types,
@@ -260,10 +258,9 @@ fn e2e_multirow_insert_all_ten_types_roundtrips_and_returning_recovers_each_type
             Some(Type::Bool),
             Some(Type::Date),
             Some(Type::DateTime),
-            Some(Type::Blob),
             Some(Type::ShortId),
         ],
-        "RETURNING recovers each of the ten playground types; got {:?}",
+        "RETURNING recovers each of the nine playground types; got {:?}",
         result.data.column_types,
     );
 
@@ -281,7 +278,7 @@ fn e2e_multirow_insert_all_ten_types_roundtrips_and_returning_recovers_each_type
         "dates round-trip: {csv:?}"
     );
 
-    let sids: Vec<&str> = rows.iter().filter_map(|r| r[9].as_deref()).collect();
+    let sids: Vec<&str> = rows.iter().filter_map(|r| r[8].as_deref()).collect();
     assert_eq!(sids.len(), 2, "both shortids present");
     assert!(
         sids.iter().all(|s| !s.is_empty()),