refactor(backend): typing for park and unpark operations

[Graffioh]

Description

Replace string-based ModelBackend::park and unpark arguments with a typed ParkTarget enum. Centralize enum/string conversion, parse daemon arguments at the protocol boundary, and preserve each backend's existing behavior for commands without an explicit target.

Validation

• Verified all ModelBackend implementations, internal callers, and test mocks use the typed API.
• git diff --check passes.
• Tests not run since the remote GPU test machine is currently offline - i can check later if needed but it's only refactor so should be fine

[cubic-dev-ai]

1 issue found across 17 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="server/src/qwen3/qwen3_backend.h">

<violation number="1" location="server/src/qwen3/qwen3_backend.h:79">
P1: Bare `park` and `unpark` commands no longer park/reload Qwen3 weights: they now pass `ParkTarget::Empty`, which this backend rejects. Preserve Qwen3's no-target behavior by treating `Empty` as including the target model in both implementations.</violation>
</file>

<sub>Reply with feedback, questions, or to request a fix.

Re-trigger cubic</sub>

[cubic-dev-ai]

P1: Bare park and unpark commands no longer park/reload Qwen3 weights: they now pass ParkTarget::Empty, which this backend rejects. Preserve Qwen3's no-target behavior by treating Empty as including the target model in both implementations.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At server/src/qwen3/qwen3_backend.h, line 79:

<comment>Bare `park` and `unpark` commands no longer park/reload Qwen3 weights: they now pass `ParkTarget::Empty`, which this backend rejects. Preserve Qwen3's no-target behavior by treating `Empty` as including the target model in both implementations.</comment>

<file context>
@@ -76,8 +76,8 @@ class Qwen3Backend : public ModelBackend {
 
-    bool park(const std::string & what) override;
-    bool unpark(const std::string & what) override;
+    bool park(ParkTarget target) override;
+    bool unpark(ParkTarget target) override;
     bool is_target_parked() const override { return parked_; }
</file context>

[Graffioh]

false positive.

before this PR "" was not considered in the condition -> it returned false

now we have ParkTarget::Empty, but qwen3 still checks only for TargetModel and DraftModel -> still return false