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/typing_surface/snapshots/typing_surface_matrix__typing_surface__create_table__after_paren_expects_type_candidates@after_paren.snap

@@ -1,5 +1,6 @@
 ---
 source: tests/typing_surface/create_table.rs
+assertion_line: 89
 description: "input=\"create table Customers with pk Code(\" cursor=36"
 expression: "& a"
 ---
@@ -45,11 +46,6 @@ Assessment {
                     kind: Keyword,
                     mode: Both,
                 },
-                Candidate {
-                    text: "blob",
-                    kind: Keyword,
-                    mode: Both,
-                },
                 Candidate {
                     text: "serial",
                     kind: Keyword,
@@ -107,11 +103,6 @@ Assessment {
                     kind: Keyword,
                     mode: Both,
                 },
-                Candidate {
-                    text: "blob",
-                    kind: Keyword,
-                    mode: Both,
-                },
                 Candidate {
                     text: "serial",
                     kind: Keyword,

tests/typing_surface/snapshots/typing_surface_matrix__typing_surface__delete_with_where__delete_with_datetime_column_says_yyyy_mm_dd_t@datetime_column.snap

@@ -1,5 +1,6 @@
 ---
 source: tests/typing_surface/delete_with_where.rs
+assertion_line: 76
 description: "input=\"delete from Things where ts=\" cursor=28"
 expression: "& a"
 ---
@@ -35,11 +36,6 @@ Assessment {
                     kind: Identifier,
                     mode: Both,
                 },
-                Candidate {
-                    text: "data",
-                    kind: Identifier,
-                    mode: Both,
-                },
                 Candidate {
                     text: "dt",
                     kind: Identifier,

tests/typing_surface/snapshots/typing_surface_matrix__typing_surface__rename_change_column__change_after_open_paren_offers_type_candidates@change_after_open_paren.snap

@@ -1,5 +1,6 @@
 ---
 source: tests/typing_surface/rename_change_column.rs
+assertion_line: 69
 description: "input=\"change column in Customers: Email (\" cursor=35"
 expression: "& a"
 ---
@@ -45,11 +46,6 @@ Assessment {
                     kind: Keyword,
                     mode: Both,
                 },
-                Candidate {
-                    text: "blob",
-                    kind: Keyword,
-                    mode: Both,
-                },
                 Candidate {
                     text: "serial",
                     kind: Keyword,
@@ -107,11 +103,6 @@ Assessment {
                     kind: Keyword,
                     mode: Both,
                 },
-                Candidate {
-                    text: "blob",
-                    kind: Keyword,
-                    mode: Both,
-                },
                 Candidate {
                     text: "serial",
                     kind: Keyword,

tests/typing_surface/snapshots/typing_surface_matrix__typing_surface__where_expression__between_expects_a_low_bound@between_low.snap

@@ -1,5 +1,6 @@
 ---
 source: tests/typing_surface/where_expression.rs
+assertion_line: 50
 description: "input=\"delete from Things where k between \" cursor=35"
 expression: "& a"
 ---
@@ -35,11 +36,6 @@ Assessment {
                     kind: Identifier,
                     mode: Both,
                 },
-                Candidate {
-                    text: "data",
-                    kind: Identifier,
-                    mode: Both,
-                },
                 Candidate {
                     text: "dt",
                     kind: Identifier,

tests/typing_surface/snapshots/typing_surface_matrix__typing_surface__where_expression__in_list_open_paren_expects_an_item@in_open_paren.snap

@@ -1,5 +1,6 @@
 ---
 source: tests/typing_surface/where_expression.rs
+assertion_line: 58
 description: "input=\"delete from Things where k in (\" cursor=31"
 expression: "& a"
 ---
@@ -35,11 +36,6 @@ Assessment {
                     kind: Identifier,
                     mode: Both,
                 },
-                Candidate {
-                    text: "data",
-                    kind: Identifier,
-                    mode: Both,
-                },
                 Candidate {
                     text: "dt",
                     kind: Identifier,