fix(python): preserve boolean const discriminators in RPC codegen

[syf2211]

Summary

Fix Python RPC codegen so JSON boolean const discriminator values are preserved instead of being coerced to strings. This restores decoding for SessionListEntry (isRemote) and QueuedCommandResult (handled).

Motivation

sessions.list() raised ValueError for any non-empty session list because the generated dispatcher matched case "true": / case "false": against Python bool values. QueuedCommandHandled.to_dict() also serialized handled as the string "true" instead of JSON boolean true.

Fixes #2122

Changes

• Add PyDiscriminatorValue helpers in scripts/codegen/python.ts to emit True/False match patterns and ClassVar[bool] defaults
• Regenerate python/copilot/generated/rpc.py
• Add unit tests covering boolean union decode/encode and SessionList.from_dict

Tests

cd python && python3 -m pytest test_rpc_generated.py -q

Result: 3 passed

Notes

• String-discriminated unions are unchanged (JSON.stringify path preserved)
• Go codegen already handled booleans correctly; Python was the only affected binding
• composer-2.5 review: APPROVE

[SteveSandersonMS]

Thanks for the fix. This duplicates #2123, which addresses the same Python boolean-discriminator codegen bug with broader test coverage and is the version we plan to proceed with, so I’m closing this PR in favor of #2123.