fix(cli): register intersection types in discoveredTypes and improve cycle detection

[izumin5210]

Why

Non-exported intersection type aliases (e.g., type Foo = A & B) were not registered in discoveredTypes, causing two issues:

1. Recursive intersection types triggered cycle detection in tryExtractAsInlineObject, silently falling back to an "Unknown" reference type — potentially leaking internal TypeScript symbols into the schema
2. Non-exported intersection types were expanded as inline objects with auto-generated names (e.g., ContainerMixed) instead of using their original alias names (NotBranded)

Summary

• Register non-exported intersection type aliases in discoveredTypes using the same logic as the alias expansion path, so recursive references resolve correctly and original alias names are preserved
• Add CYCLE_DETECTED diagnostic code and FieldTypeResolverDiagnostic infrastructure as a safety net — when a cycle is detected with no valid reference target (not in knownTypeNames or discoveredTypes), emit a warning and skip the field instead of silently falling back
• Improve cycle detection to check type.aliasSymbol as fallback (intersection types may lack type.symbol)
• Add intersection-type-discovery golden test case verifying recursive intersection type resolution
• Update branded-type-not-branded golden snapshots to reflect improved naming

Test plan

• intersection-type-discovery golden test: non-exported recursive intersection type resolves correctly with original alias name
• branded-type-not-branded golden test: updated to reflect alias name usage
• All 464 golden tests pass
• Type check passes

🤖 Generated with Claude Code

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[github-actions]

Code Metrics Report

	main (9ed4962)	#219 (e1986f5)	+/-
Coverage	88.4%	88.4%	-0.1%
Test Execution Time	10m34s	10m48s	+14s

Details

  |                     | main (9ed4962) | #219 (e1986f5) |  +/-  |
  |---------------------|----------------|----------------|-------|
- | Coverage            |          88.4% |          88.4% | -0.1% |
  |   Files             |             78 |             78 |     0 |
  |   Lines             |           5322 |           5344 |   +22 |
+ |   Covered           |           4708 |           4726 |   +18 |
- | Test Execution Time |         10m34s |         10m48s |  +14s |

Code coverage of files in pull request scope (87.8% → 87.6%)

Files	Coverage	+/-	Status
packages/cli/src/resolver-extractor/extractor/define-api-extractor.ts	88.8%	0.0%	modified
packages/cli/src/type-extractor/extractor/field-type-resolver.ts	91.6%	-0.7%	modified
packages/cli/src/type-extractor/extractor/type-extractor.ts	85.1%	-0.2%	modified

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Reported by octocov