Recover Java switch emission and preserve colliding source outputs

[LLeavesG]

Summary

• infer null-select reference types, erase non-denotable method bounds, and isolate nested field namespaces
• preserve case-colliding source files when writing a class shard to disk
• keep Kotlin reification markers and non-void call results from dropping their continuations
• return switch results directly, join complementary boolean branches, flatten terminal void tails, and reconstruct lowered string switches
• preserve cmp operand evaluation and simplify repeated stable conditional arms
• materialize shared vacuous predicate values before they are replayed by a later effect

This is one Java emission and semantic-normalization pipeline presented as 13 scoped commits. The CLI case-collision change is merged with the existing fail-soft save path so a write error still skips the rest of the shard only when --fail-fast is off.

Two earlier exception-cleanup commits remain on the ledger: they regress syncWithFinally / structured finally when stacked on current main.

Validation

• cargo fmt --all -- --check
• cargo check -p dexdec -p dexdec-workbench -p dexdec-mcp
• cargo test -p dexdec --lib (569 passed)
• 36 added regression scenarios
• cargo test -p dexdec --test expected_test
• cargo test -p dexdec --test cli_args_test
• node --test scripts/version.test.mjs and node scripts/version.mjs check

Review notes

The commits move from Java type legality through CLI output identity to switch/branch reconstruction, so they can be reviewed in that order.