fix(portal): tolerate pre-#988 guest missing Container.Start

[DorianZheng]

Problem

PR #988 split the guest's fused Container.Init into Init (create) + Start (run init). The guest agent is baked into the versioned guest-rootfs and reused per-box across restarts, so a box created before #988 boots its old agent — which has no Container.Start. The post-#988 host calls it, tonic returns Unimplemented, and it surfaced as gRPC/tonic error … Unimplemented … (code=16), breaking restart/exec of pre-#988 boxes.

Fix

ContainerInterface::start now reads the gRPC status before ? flattens it and treats Unimplemented as "already started": on a pre-#988 agent the fused Init (still called every boot) already ran init, so Start is a redundant no-op. Real errors still propagate.

Also removes the spurious boxlite/gvproxy feature from sdks/c (introduced in #994), which linked the shim-side libgvproxy-sys CGO library into the C SDK — the SDK/CLI must not, per the existing net::tests guard. Matches Python/Node/CLI, which expose the same tunnel API with rest only.

Test

An in-process tonic stub guest returning Unimplemented reproduces the exact failure through ContainerInterface::start; the degrade turns it green while a genuine Start error still surfaces. Full boxlite + boxlite-shared unit suites pass (852 + 47).

Deferred: the durable fix (re-inject/recreate the guest so restarts run the current agent, kata/Daytona-style) is not included here.

https://claude.ai/code/session_01Vu4qDgCnMjnLPpNsroxeAP

Summary by CodeRabbit

• Bug Fixes
  • Container startup now succeeds when the service reports that the container start operation is unsupported, treating it as already started.
  • Genuine container startup errors continue to be reported normally.
• Compatibility
  • Updated SDK configuration to use the REST feature without the optional networking feature.

[boxlite-agent]

📦 BoxLite review — couldn't complete

claude exited 1

stdout:
{"is_error":true,"duration_api_ms":0,"num_turns":1,"stop_reason":"stop_sequence","session_id":"abb061ce-5747-41b2-86bd-7007e707be9f","total_cost_usd":0,"usage":{"input_tokens":0,"cache_creation_input_tokens":0,"cache_read_input_tokens":0,"output_tokens":0,"server_tool_use":{"web_search_requests":0,"web_fetch_requests":0},"service_tier":"standard","cache_creation":{"ephemeral_1h_input_tokens":0,"ephemeral_5m_input_tokens":0},"inference_geo":"","iterations":[],"speed":"standard"},"modelUsage":{},"permission_denials":[],"terminal_reason":"api_error","fast_mode_state":"off","subtype":"success","api_error_status":403,"result":"Your organization has disabled Claude subscription access for Claude Code · Use an Anthropic API key instead, or ask your admin to enable access","type":"result","duration_ms":375,"uuid":"3b38f726-125f-44f9-a944-769bda4bac21"}

stderr:
<empty>

_{powered by BoxLite}

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[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 8bc60ea3-c5d7-41aa-9875-90fe7593cce7

📥 Commits

Reviewing files that changed from the base of the PR and between 015503d and 392631e.

📒 Files selected for processing (2)

• sdks/c/Cargo.toml
• src/boxlite/src/portal/interfaces/container.rs

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📝 Walkthrough

Walkthrough

Container startup now treats gRPC Unimplemented responses as successful, preserves propagation of other errors, and adds tests for unimplemented, failure, and success responses. The C SDK no longer enables the gvproxy feature for BoxLite dependencies.

Changes

Container startup compatibility

Layer / File(s)	Summary
C SDK dependency features sdks/c/Cargo.toml	The regular and development BoxLite dependencies enable only the rest feature; the build dependency remains unchanged.
Container start response handling src/boxlite/src/portal/interfaces/container.rs	ContainerInterface::start returns success for Unimplemented, propagates other start errors, and tests unimplemented, failing, and successful server responses.

Estimated code review effort: 2 (Simple) | ~10 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title is concise and accurately summarizes the main compatibility fix in the PR.
Description check	✅ Passed	It covers the problem, fix, and test evidence, though it doesn't follow the template headings or include a formal risks/rollout section.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

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