fix: harden migration command execution

Two problems in the migration commands: no timeouts, and SQL split on literal
bytes.

`migrations:plan` and `migrations:apply` constructed their connection with
neither a connection deadline nor an operation deadline — a real server reported
`statement_timeout = 0` on the migration connection. Both now default to 10
seconds for the connection deadline, the client query timeout, and PostgreSQL's
own statement_timeout, applied at the one shared construction boundary so a
future call site cannot silently omit them. History reads, advisory-lock
queries, transaction control, migration SQL, and history writes are all covered.
The existing lock-wait deadline, the Pass 2 TLS policy, and Doctor's and the
bootstrap CLI's own timeouts are untouched, and no environment variable or flag
was added.

Explicit client fields do not win under the pinned driver. [email protected].0 builds
parameters as `Object.assign({}, config, parse(config.connectionString))`, so
the URL overrides passed options — verified directly, where an explicit
statement_timeout of 10000 alongside `?statement_timeout=0` produced a
server-reported 0, while a clean URL produced 10s. A DATABASE_URL carrying
connect_timeout, query_timeout, statement_timeout, or an `options` value setting
statement_timeout is therefore refused with the existing fixed configuration
error, before any client is constructed and without echoing the URL, parameter,
or value. Unrelated parameters are left alone.

The runner split each migration on the literal `--> statement-breakpoint` bytes.
Those bytes inside a string literal, a dollar-quoted function body, a quoted
identifier, or a comment tore the migration into fragments that were no longer
valid SQL — each case verified to produce two fragments where one was required.
Each migration's exact SQL is now passed to the client once, with no values and
no prepared-statement name, inside the existing transaction, and its history row
inserted only after that batch succeeds. One transaction still spans all pending
migrations; advisory locking, checksum validation, approval preflight, ordering,
rollback, cleanup, and sanitized error identity are unchanged. The port method
is renamed executeStatement to executeMigrationSql so the contract says what it
receives.

PostgreSQL parses the batch because it owns the only correct parser. A homegrown
splitter would have to track single quotes, dollar quoting with arbitrary tags,
quoted identifiers, line comments, nested block comments, and escape syntax to
answer a question the server already answers, and a parser dependency would add
supply-chain surface for the same reason. Drizzle's marker lines are ordinary
`--` comments when the batch is sent whole. No custom SQL parser exists here.

Co-Authored-By: Claude Opus 5 <[email protected]>

docs/architecture/decisions/0009-transactional-module-migrations.md

@@ -90,6 +90,16 @@ aggregate order, and its history row is inserted only after that migration succe
 failure rolls back every schema change and history insert from the current invocation. Migrations
 committed by earlier invocations remain applied.
 
+> **Partial correction — see [ADR 0020](0020-module-runtime-and-migration-execution-hardening.md).**
+> Splitting on the literal marker, described in the paragraph immediately below, split a migration
+> whose SQL legitimately contained those bytes inside a string literal, dollar-quoted body, quoted
+> identifier, or comment. Core now sends each migration's complete SQL to PostgreSQL in one call
+> inside the same transaction, so the server does all SQL parsing and the marker lines are ordinary
+> `--` comments. Everything else recorded here — one transaction across the pending batch, history
+> rows inserted only after their migration succeeds, no semicolon splitting, no parsing,
+> classifying, reordering, or repairing SQL, and no non-transactional fallback — is unchanged and
+> still accepted. This section is left as originally accepted, as the historical record.
+
 Core matches Drizzle's generated statement-breakpoint behavior: it splits only on the exact
 literal `--> statement-breakpoint` marker. It never splits SQL on semicolons or tries to parse,
 classify, reorder, or repair arbitrary SQL. Transaction-incompatible SQL fails the transaction;