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/seed/generators.rs

@@ -138,7 +138,7 @@ fn range_value(low: &str, high: &str, ty: Type, rng: &mut SeedRng) -> Value {
         Type::DateTime => parse_datetime_range(low, high)
             .map(|(lo, hi)| Value::Text(random_datetime_between(rng, lo, hi)))
             .unwrap_or_else(|| generic_for_type(ty, rng)),
-        // text / bool / blob / shortid have no range meaning.
+        // text / bool / shortid have no range meaning.
         _ => generic_for_type(ty, rng),
     }
 }
@@ -155,8 +155,8 @@ pub fn range_bounds_reason(ty: Type, low: &str, high: &str) -> Option<String> {
         Type::Real | Type::Decimal => parse_real_range(low, high).is_some(),
         Type::Date => parse_date_range(low, high).is_some(),
         Type::DateTime => parse_datetime_range(low, high).is_some(),
-        // text / bool / blob / shortid have no range meaning.
-        Type::Text | Type::Bool | Type::Blob | Type::ShortId => false,
+        // text / bool / shortid have no range meaning.
+        Type::Text | Type::Bool | Type::ShortId => false,
     };
     if ok {
         return None;
@@ -169,7 +169,7 @@ pub fn range_bounds_reason(ty: Type, low: &str, high: &str) -> Option<String> {
             "expected two quoted datetimes, e.g. `between '2023-01-01T00:00:00' and '2024-12-31T23:59:59'`"
                 .to_string()
         }
-        Type::Text | Type::Bool | Type::Blob | Type::ShortId => {
+        Type::Text | Type::Bool | Type::ShortId => {
             "a `between` range only applies to numeric and date/datetime columns".to_string()
         }
     })
@@ -242,9 +242,8 @@ fn random_datetime_between(
 }
 
 /// Type-based fallback generation (D8). Never produces NULL for a
-/// generatable type; `blob`/`serial`/`shortid` are handled by the
-/// executor (autogen / block guard) and yield NULL here only as a
-/// last resort.
+/// generatable type; `serial`/`shortid` are handled by the executor
+/// (autogen) and yield NULL here only as a last resort.
 fn generic_for_type(ty: Type, rng: &mut SeedRng) -> Value {
     use fake::faker::lorem::en as lorem;
     match ty {
@@ -267,7 +266,6 @@ fn generic_for_type(ty: Type, rng: &mut SeedRng) -> Value {
         Type::Bool => Value::Bool(rng.random_range(0..2) == 1),
         Type::Date => Value::Text(format_date(random_past_date(rng, 0, RECENT_WINDOW_DAYS))),
         Type::DateTime => Value::Text(random_recent_datetime(rng)),
-        Type::Blob => Value::Null,
     }
 }
 
@@ -705,10 +703,6 @@ mod tests {
             generate_value(&Generator::Generic, Type::Bool, &mut rng),
             Value::Bool(_)
         ));
-        assert!(matches!(
-            generate_value(&Generator::Generic, Type::Blob, &mut rng),
-            Value::Null
-        ));
         // shortid fallback is a valid base58 id.
         let Value::Text(sid) = generate_value(&Generator::Generic, Type::ShortId, &mut rng) else {
             panic!("shortid not text")