test(release): prove packaged Windows client-server login

[zoeyrose]

Summary

Closes #521

The packaged Windows review smoke now proves a production client/server login through an isolated account and character, reaches the gameplay-ready state, and shuts both processes down cleanly. Local offline startup is deterministic and records bounded network diagnostics without logging URLs or secrets.

Implementation / behavior

• The flat Windows review bundle provisions a disposable account and character through the packaged server scenario provisioner, then launches the production client with the exact QUIC certificate pin and existing --connect account/password/character automation.
• The server and client use loopback-only networking, http_url=off, --nometa, --game_news_url=off, --stun_server=off, and port mapping disabled. cURL requests name their bounded subsystem origin and endpoint class without retaining credentials in the diagnostic.
• The Windows smoke waits for server readiness, connection, server-side character acceptance, and client gameplay readiness; it then closes the client normally and requires graceful server shutdown with zero exit codes.

Validation

• Focused composer and workflow-contract tests cover the generated launcher, isolated scenario, offline policy, readiness markers, and graceful teardown.
• The Windows validation job executes the production package smoke and the existing server-package smoke on the native runner.
• Classic import-history, owner validation, diff, build, and test checks remain required for the final head.

Limitations / follow-up

• Final package acceptance remains dependent on the GitHub Windows runner having its supported GPU/display environment; no merge or issue closure is performed by this delivery.

[codecov]

Codecov Report

❌ Patch coverage is 55.01859% with 121 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
client/src/client/gpu_player_view.c	9.09%	20 Missing ⚠️
libatrinik/tests/curl.c	75.00%	6 Missing and 13 partials ⚠️
client/src/client/main.c	55.00%	13 Missing and 5 partials ⚠️
client/src/client/gpu_renderer.c	34.78%	11 Missing and 4 partials ⚠️
libatrinik/curl.c	68.08%	6 Missing and 9 partials ⚠️
libatrinik/tests/path.c	31.81%	0 Missing and 15 partials ⚠️
client/src/gui/misc/game_news.c	0.00%	5 Missing ⚠️
client/src/gui/misc/intro.c	0.00%	5 Missing ⚠️
client/src/client/asset_source.c	0.00%	1 Missing ⚠️
client/src/client/commands.c	0.00%	1 Missing ⚠️
... and 7 more

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