feat(code-queue): register minimax-m3 alongside minimax-m2.7

Add minimax-m3 as a sibling model on the same path as the existing
minimax-m2.7 support. M3 is the new PROD default; M2.7 remains available
as a one-line rollback target via MINIMAX_MODEL.

Changes:
- code-agent/common.ts: add minimaxM3Model constant, include in
  defaultCodeModels, normalize aliases (minimax-m3 / m3), route to
  opencode port, sibling entry in codeModelProviderSourceContract.
- code-agent/opencode.ts: add M3 branch in openCodeModelId, register
  both M2.7 and M3 in openCodeConfigContent, inject MINIMAX_M3_MODEL
  in local/remote env, M3 branch in missingOpenCodeCredentialMessage.
- index.ts + types.ts: add minimaxM3Model to RuntimeConfig, read
  MINIMAX_M3_MODEL env, propagate to remoteCodexEnvKeys.
- queue-api.ts: include minimaxM3Model in Pick for
  codeModelProviderSourceContract callers.
- scripts/src/code-queue.ts: add minimaxM3SubmitModel, normalize/port
  routing, default route recommendation now points to M3, M2.7 kept
  as minimaxM2FallbackCandidate.
- scripts/src/docker.ts: default UNIDESK_CODE_QUEUE_MINIMAX_M3_MODEL
  to MiniMax-M3.
- k8s yaml (D601 + G14): CODE_QUEUE_MODELS gains minimax-m3, three
  deployments each set MINIMAX_MODEL=MiniMax-M3 and
  MINIMAX_M3_MODEL=MiniMax-M3.
- docker-compose.d601.yml: same env defaults for local compose.
- docs/reference/{code-queue-supervision,microservices,
  windows-passthrough}.md: update model contracts to M3 default +
  M2.7 fallback.
- scripts/code-queue-submit-routing-contract-test.ts: low-risk
  recommendation now asserts minimax-m3; registry asserts both M3
  and M2.7 fallback in modelPorts/opencodeModels; provider source
  contract test passes minimaxM3Model.

Refs: #189

scripts/src/code-queue.ts

@@ -51,6 +51,7 @@ const detailInitialPromptPreviewChars = 1200;
 const detailBasePromptPreviewChars = 800;
 const detailLastAssistantPreviewChars = 1200;
 const minimaxSubmitModel = "minimax-m2.7";
+const minimaxM3SubmitModel = "minimax-m3";
 const deepseekSubmitModel = "deepseek-chat";
 const gptSubmitModel = "gpt-5.5";
 const submitLockWaitMs = 60_000;
@@ -1300,6 +1301,7 @@ function normalizeSubmitModel(value: string | null | undefined): string {
   const lower = raw.toLowerCase();
   const leaf = lower.includes("/") ? lower.split("/").at(-1) ?? lower : lower;
   if (leaf === minimaxSubmitModel || leaf === "m2.7") return minimaxSubmitModel;
+  if (leaf === minimaxM3SubmitModel || leaf === "m3") return minimaxM3SubmitModel;
   if (leaf === deepseekSubmitModel || leaf === "deepseek") return deepseekSubmitModel;
   return raw;
 }
@@ -1322,7 +1324,7 @@ function submitModelRegistry(models: string[] = sharedDefaultCodeModels): {
 function submitRunnerForModel(model: string | null | undefined): "opencode" | "codex" | null {
   const normalized = normalizeSubmitModel(model);
   if (normalized.length === 0) return null;
-  return normalized === minimaxSubmitModel || normalized === deepseekSubmitModel ? "opencode" : "codex";
+  return normalized === minimaxSubmitModel || normalized === minimaxM3SubmitModel || normalized === deepseekSubmitModel ? "opencode" : "codex";
 }
 
 function regexEvidence(text: string, patterns: RegExp[], limit = 6): string[] {
@@ -1574,11 +1576,17 @@ function submitPolicyContract(): SubmitRoutingRecommendation["policyContract"] {
         requiredGuards: ["self-contained prompt", "limited write scope", "contract/unit verification", "commander review"],
       },
       {
-        model: minimaxSubmitModel,
+        model: minimaxM3SubmitModel,
         runner: "opencode",
         taskRisk: "simple-low-risk",
         requiredGuards: ["issue is auxiliary only", "evidence required", "no prod/secrets/DB writes", "diff and test review"],
       },
+      {
+        model: minimaxSubmitModel,
+        runner: "opencode",
+        taskRisk: "simple-low-risk-fallback",
+        requiredGuards: ["issue is auxiliary only", "evidence required", "no prod/secrets/DB writes", "diff and test review"],
+      },
     ],
     externalProvider429: {
       commanderAction: "wait-while-exponential-backoff-is-healthy",
@@ -1741,15 +1749,15 @@ function submitRoutingRecommendation(options: CodexSubmitOptions): SubmitRouting
   } else if (promptSelfContained && issueIsNotOnlySource && evidenceRequiredByPrompt && lowRiskEvidence.length > 0) {
     route = "minimax-opencode";
     recommendedRunner = "opencode";
-    recommendedModel = minimaxSubmitModel;
+    recommendedModel = minimaxM3SubmitModel;
     confidence = "high";
-    reason = "The prompt looks self-contained, low-risk, and asks for verifiable evidence; it is a MiniMax/OpenCode candidate if the runner smoke is currently green.";
+    reason = "The prompt looks self-contained, low-risk, and asks for verifiable evidence; it is a MiniMax M3/OpenCode candidate if the runner smoke is currently green.";
   } else if (lowRiskEvidence.length > 0 && issueIsNotOnlySource && noProdRestartSecretOrDbWrite) {
     route = "minimax-opencode";
     recommendedRunner = "opencode";
-    recommendedModel = minimaxSubmitModel;
+    recommendedModel = minimaxM3SubmitModel;
     confidence = "medium";
-    reason = "The prompt has low-risk signals, but the commander should tighten self-contained context and evidence requirements before relying on MiniMax.";
+    reason = "The prompt has low-risk signals, but the commander should tighten self-contained context and evidence requirements before relying on MiniMax M3.";
   }
 
   const explicitNote = model.length === 0
@@ -7963,7 +7971,8 @@ function codexSubmitTask(args: string[]): unknown {
       },
       commands: {
         submitAsRequested: "remove --dry-run to submit exactly this payload",
-        minimaxCandidate: `bun scripts/cli.ts codex submit --prompt-file <path> --model ${minimaxSubmitModel} --dry-run`,
+        minimaxCandidate: `bun scripts/cli.ts codex submit --prompt-file <path> --model ${minimaxM3SubmitModel} --dry-run`,
+        minimaxM2FallbackCandidate: `bun scripts/cli.ts codex submit --prompt-file <path> --model ${minimaxSubmitModel} --dry-run`,
         deepseekCandidate: `bun scripts/cli.ts codex submit --prompt-file <path> --model ${deepseekSubmitModel} --dry-run`,
         gptCandidate: `bun scripts/cli.ts codex submit --prompt-file <path> --model ${gptSubmitModel} --dry-run`,
       },