fix inline struct field access and revert TryStatement flattening

[cs01]

Summary

• Fix a root cause bug in storeInterfaceMetadata where accessing fields on anonymous nested struct types (like stmt.catchClause.body) silently produced wrong values. Added a third branch that parses inline { field: type; ... } type strings and stores proper metadata for chained member access.
• Revert the TryStatement flattening workaround (catchParam/catchBody → nested catchClause: { param, body }) now that the root cause is fixed. This restores the natural TypeScript representation.
• Add code style guidelines to .claude/rules.md (prefer named AST types, comment style for codegen blocks).

Changed files

• src/codegen/expressions/access/member.ts — new inline struct branch in storeInterfaceMetadata
• src/ast/types.ts — TryStatement uses nested catchClause again
• src/parser-ts/handlers/statements.ts — produce catchClause: { param, body }
• src/parser-native/transformer.ts — produce catchClause: { param, body }
• src/analysis/semantic-analyzer.ts — read catchClause.param / catchClause.body
• src/ast/visitor.ts — walk catchClause.body
• src/codegen/infrastructure/closure-analyzer.ts — walk catchClause.body
• src/codegen/statements/control-flow.ts — read catchClause.param / catchClause.body
• .claude/rules.md — code style section

Test plan

• All 279 tests pass (only pre-existing network test failures from missing lws-bridge.o)
• All 4 try/catch test fixtures pass with the nested catchClause struct
• Self-hosting Stage 0 + Stage 1 pass
• Stage 1 proves the fix works end-to-end: the native compiler correctly compiles code that accesses catchClause.body through the inline struct metadata path