fix(ddlmod): parse parameterized types with precision like decimal(10,2)

[h2zi]

Symptom

For a column declared decimal(10,2), ColumnTypes() reports ColumnType() == "decimal(10" — the type group of columnRegexp ([\w\(\)\d]+) has no comma, so the match stops inside the parameter list and the scale is lost entirely (related: #121).

Fix

• The type group now captures the whole parenthesized parameter list: \w+(?:\([^)]*\))?.
• Size parsing distinguishes a single length from precision+scale: varchar(10) → Length() == 10 as before, decimal(10,2) (and decimal(10, 2)) → DecimalSize() == (10, 2), with DataType() == "decimal" and the full ColumnType() preserved.

Covered by TestParseDDL_TypePrecision.

🤖 Generated with Claude Code

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Merge order (this batch: #241 → #242 → #243 → #244 → #245 → #246, plus #234 from the previous batch): all seven are functionally independent and merge cleanly in any order. Several append tests to the same test files, so whichever merges later may show a trivial append-only conflict in migrator_test.go/ddlmod_test.go — I'll rebase the remaining ones promptly after each merge, as before.

[Copilot]

Pull request overview

This PR fixes SQLite DDL parsing so parameterized column types that include commas (e.g. decimal(10,2)) are captured and interpreted correctly by the migrator’s ColumnTypes()/ColumnType()/size helpers.

Changes:

• Updates columnRegexp to capture a full parenthesized type parameter list (including commas) instead of truncating at the first comma.
• Replaces the previous numeric-suffix extraction with a dedicated typeSizeRegexp that parses either length or precision,scale.
• Adds TestParseDDL_TypePrecision to validate decimal(10,2), decimal(10, 2), and varchar(25) behavior, including preservation of full ColumnType().

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
ddlmod.go	Improves type tokenization and parses (len) vs (precision,scale) using a dedicated regexp.
ddlmod_test.go	Adds a regression test ensuring decimal precision/scale and full column type strings are preserved.

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