fix: push variant renames and default switches to the platform

[Ruari-Phipps]

Summary

Renaming a variant to a name with the same "clean name" (e.g. only the punctuation changes) was silently dropped on push, and a new variant marked is_default never actually became the default. Both are fixed, and set-default command emission moves out of queue_resources into _stage_commands.

Motivation

Variant.file_path is derived from clean_name(), which maps punctuation and whitespace to _. So renaming a variant from My Variant - Prod to My_Variant - Prod keeps the same path: the variant is treated as kept rather than delete+create, and its changed hash puts it in updated_resources. But Variant.build_update_proto returned Variant_SetDefaultVariant, which has no name field, so the rename never reached the platform — while local state and file_structure_info were rewritten as if the push had succeeded, leaving local and remote permanently out of sync with no error.

Separately, Variant_CreateVariant has no is_default field, and the only thing emitting a set-default command was the update path, which new resources never reach. A variant created with is_default: true therefore never became the default.

prepush.filter_nondefault_variant_updates dropped every update for a non-default variant. That was only safe because "update" literally meant "set default"; once updates carry a name it would suppress legitimate renames, so it is removed.

Changes

• Variant.update_command_type is now variant_update_variant, and build_update_proto returns Variant_UpdateVariant(id, name), so renames reach the platform.
• attribute_values on that proto is deliberately left unset. The platform only rewrites a variant's attribute values when the field is present, and a present map must cover every non-archived attribute or the command is rejected — sending it would risk wiping values. There is a regression test guarding this.
• Set-default emission moves out of AgentStudioInterface.queue_resources into queue_set_default_commands in poly/utils/commands.py, called at the end of AgentStudioProject._stage_commands, for both handoffs and variants. It has to run after the creates and updates, because the platform rejects a set-default for a resource that does not exist yet. This is what fixes the new-default-variant case.
• queue_resources goes back to being purely generic (deletes → creates → updates, duck-typed on *_command_type / build_*_proto) with no per-resource-type knowledge.
• prepush.filter_nondefault_variant_updates removed, along with its call site and a stale docstring line.
• New create_command_handoff_set_default / create_command_variant_set_default builders alongside the existing standalone command builders.

Test strategy

• Added/updated unit tests
• Manual CLI testing (poly <command>)
• Tested against a live Agent Studio project
• N/A (docs, config, or trivial change)

Checklist

• ruff check . and ruff format --check . pass
• pytest passes
• No breaking changes to the poly CLI interface (or migration path documented)
• Commit messages follow conventional commits

Screenshots / Logs

ruff check .          All checks passed!
ruff format --check . 95 files already formatted
pytest                1445 passed, 117 subtests passed

🤖 Generated with Claude Code

[github-actions]

Coverage Report

Base (main)	PR	Change
76.5%	76.7%	+0.2% ✅

Changed file coverage

File	Coverage	Change
poly/handlers/interface.py	64.3%	+1.2% ✅
poly/project.py	76.4%	+0.0% ✅
poly/resources/handoff.py	86.4%	+3.2% ✅
poly/resources/variant_attributes.py	87.9%	+2.3% ✅
poly/utils/prepush.py	95.0%	+1.1% ✅
poly/utils/commands.py	96.4%	+6.4% ✅