Split `TypeRepository.kt`; merge the two parallel type tables

[MariusVolkhart]

Depends on: #276 (moves quoteSqlIdentifierIfNeeded out of this file first).

Why

generator/src/main/kotlin/norm/generator/TypeRepository.kt is 1145 lines holding four unrelated
things:

Lines	Concern
26-552	TypeRepository class: column → SqlMappable resolution and data-class projection building
554-795	Two type tables: BASE_TYPE_RESOLVERS (35 keys → SqlMappable factory) and resolveJdbcTypeInfo (the same 35 keys → JdbcTypeInfo), plus postgresArrayElementTypeName
797-1100	KDoc rendering: PropertySource, addClassKdoc, formatAsKdocPropertyReference, needsKotlinPoetDeclarationBackticks, sourceReference, and the Markdown helpers (longestBacktickRun, markdownInlineCodeSpan, containsUnescapableBlockCommentDelimiter, escapeMarkdownBacktick, wrapInBacktickDelimiter, markdownFenceDelimiter)
1102-1145	collapseCosmeticWhitespace (a lexer-aware whitespace normaliser used by the provenance path)

The two type tables are kept in lockstep by a test sweep (ColumnTypeMappingTest.kt, the
DomainBaseTypes parity check around lines 2185-2200) rather than by construction. A type added to
one and forgotten in the other compiles and fails only at test time.

Target state

Files

• TypeRepository.kt: the class only (lines 26-552 today), plus ENUM_JDBC_TYPE_INFO if only the
  class uses it.
• PostgresBaseTypes.kt: the merged table (below) and postgresArrayElementTypeName.
• KdocRendering.kt: PropertySource, TypeSpec.Builder.addClassKdoc, every private helper it
  calls, and the Markdown helpers. InterfaceBuilder.kt already imports markdownFenceDelimiter,
  escapeMarkdownBacktick, containsUnescapableBlockCommentDelimiter; those stay internal.
• collapseCosmeticWhitespace moves to SqlLexer.kt: it is a skipLexicalToken-based text
  normaliser and its only callers are TypeRepository.buildTypeProjectionForQuery and
  resolveNodeTreeProvenanceExpression.

Pure moves: no function body changes in this step. Do the split as its own commit so the diff is
reviewable as renames.

Merged table

/**
 * One Postgres base type Norm maps to Kotlin, keyed by its canonical or SQL-standard spelling.
 *
 * @property mappable Builds the [SqlMappable] for a plain (adapterless) column of this type.
 * @property jdbcTypeInfo The wire-level getter/setter description used when the same type sits behind a
 *   [ColumnAdapter] (an enum, a domain, or a user type mapping).
 */
internal class PostgresBaseType(
  val mappable: (notNull: Boolean) -> SqlMappable,
  val jdbcTypeInfo: JdbcTypeInfo,
)

internal val POSTGRES_BASE_TYPES: Map<String, PostgresBaseType> = buildMap {
  fun register(jdbcTypeInfo: JdbcTypeInfo, vararg names: String, mappable: (Boolean) -> SqlMappable) {
    for (name in names) put(name, PostgresBaseType(mappable, jdbcTypeInfo))
  }
  register(JdbcTypeInfo("getShort", "setShort", true, "SMALLINT", kotlinType = SHORT), "smallserial", "serial2", "smallint", "int2") {
    JdbcTypes.SHORT.decorateForNullable(it)
  }
  // ... one register call per row of today's resolveJdbcTypeInfo `when`, carrying the matching
  // BASE_TYPE_RESOLVERS lambda ...
}

internal fun resolveJdbcTypeInfo(baseTypeName: String): JdbcTypeInfo? = POSTGRES_BASE_TYPES[baseTypeName]?.jdbcTypeInfo

TypeRepository.resolveBaseType becomes
POSTGRES_BASE_TYPES[typeName.removePrefix("pg_catalog.")]?.mappable?.invoke(notNull).

Keep every existing comment that carries a verified fact (pgjdbc getter behaviour for java.time
types, oid → Blob, json/jsonb needing Types.OTHER) attached to the row it describes. Drop
the paragraphs whose only content is "the two tables must be kept in sync"; there is now one table.

Tests

The parity sweep in ColumnTypeMappingTest that asserts every BASE_TYPE_RESOLVERS key has a
resolveJdbcTypeInfo entry becomes a tautology (x in map.keys → map[x] != null). Delete it. Keep
the alias-classification test around line 1025 (it asserts something about
postgresArrayElementTypeName, not table parity); rewrite its BASE_TYPE_RESOLVERS.keys reference to
POSTGRES_BASE_TYPES.keys. Every other test that names BASE_TYPE_RESOLVERS is updated the same way.
TypeRepositoryTest.kt, DomainBuilderTest.kt, and the golden scenarios (all_types, domains,
type_mappings) pin the per-type output.

Acceptance criteria

1. No file under generator/src/main exceeds 1000 lines after this change except
   PgNodeTreeParser.kt and NodeTreeNullabilityAnalyzer.kt (addressed elsewhere or accepted).
2. git grep -n "BASE_TYPE_RESOLVERS" generator/ returns nothing; exactly one table maps type names.
3. ./gradlew :generator:check :gradle-plugin:test passes; golden regeneration leaves
   test-scenarios* byte-identical.

Files

• generator/src/main/kotlin/norm/generator/TypeRepository.kt (shrinks)
• new generator/src/main/kotlin/norm/generator/PostgresBaseTypes.kt
• new generator/src/main/kotlin/norm/generator/KdocRendering.kt
• generator/src/main/kotlin/norm/generator/SqlLexer.kt (receives collapseCosmeticWhitespace)
• generator/src/main/kotlin/norm/generator/DomainBuilder.kt, Main.kt (import-only changes)
• generator/src/test/kotlin/norm/generator/ColumnTypeMappingTest.kt

---

Conventions every issue inherits

• Repo root: /Volumes/Code/3rd-party/norm. Module under change is almost always generator/.
• Style: 2-space indent, 120 columns, full words in identifiers (parameter, not param), no
  section-separator comments, @Nested classes group tests. Format with ./gradlew spotlessApply.
• TDD: tests are written first or alongside. For a behavior-preserving refactor the existing suite is
  the pin; each issue says which tests must also be added.
• Golden files under test-scenarios*/ are never hand-edited. A refactor is behavior-preserving only
  if ./gradlew :gradle-plugin:generateGoldenFiles leaves git status --porcelain test-scenarios test-scenarios-frameworks empty.
• Verification for a generator/ change: ./gradlew :generator:check :gradle-plugin:test (Docker
  required). Then the golden regeneration check above.
• Commit message explains the design decision, not the diff.
• Never run ./gradlew clean or disable the configuration/build cache to "fix" a build problem.