feat(opencode): remplace le provider Ollama par llama.cpp

Le tool-calling local ne fonctionnait jamais via Ollama. Refonte du
support local d'OpenCode autour de llama.cpp: profil, catalogue,
matérialisation de la config OpenCode et surface first-run alignés sur
llama-server (backend + frontend).

QA vert (commandes réelles): domain 244, application 81+64, infra 263
(10 échecs = bind-port sandbox identiques sur develop, non-régression),
frontend 574, tsc propre. Réserve E2E live non bloquante faute de
llama-server joignable.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/features/first-run/profile.test.ts

@@ -9,6 +9,7 @@ import type { AgentProfile } from "@/domain";
 import {
   defaultHttpChatConfig,
   defaultInjection,
+  defaultOpenCodeConfig,
   emptyCustomProfile,
   isProfileValid,
   isRelativeSafe,
@@ -16,6 +17,7 @@ import {
   isValidHttpUrl,
   parseArgs,
   validateHttpChatConfig,
+  validateOpenCodeConfig,
   validateProfile,
 } from "./profile";
 
@@ -189,6 +191,58 @@ describe("validateProfile for openAiCompatible profiles", () => {
   });
 });
 
+describe("validateOpenCodeConfig", () => {
+  it("a well-formed llama.cpp config is valid", () => {
+    expect(validateOpenCodeConfig(defaultOpenCodeConfig())).toEqual({});
+  });
+  it("reports a bad base URL scheme and an empty model", () => {
+    const errors = validateOpenCodeConfig({ baseURL: "ftp://x", model: "  " });
+    expect(errors.baseURL).toBeDefined();
+    expect(errors.model).toBeDefined();
+  });
+  it("an optional API key is free-form (no env-var-name constraint)", () => {
+    // Unlike the openAiCompatible adapter, OpenCode carries the key itself.
+    expect(
+      validateOpenCodeConfig({
+        baseURL: "http://localhost:8080/v1",
+        apiKey: "sk-secret-123",
+        model: "qwen3-coder-30b",
+      }),
+    ).toEqual({});
+  });
+});
+
+describe("validateProfile for openCode profiles", () => {
+  function opencode(overrides: Partial<AgentProfile> = {}): AgentProfile {
+    return base({
+      name: "OpenCode + llama.cpp",
+      command: "opencode",
+      structuredAdapter: "openCode",
+      opencode: defaultOpenCodeConfig(),
+      ...overrides,
+    });
+  }
+  it("the reference llama.cpp profile is valid", () => {
+    expect(validateProfile(opencode())).toEqual({});
+    expect(isProfileValid(opencode())).toBe(true);
+  });
+  it("surfaces opencode field errors through the profile validator", () => {
+    const errors = validateProfile(
+      opencode({ opencode: { baseURL: "nope", model: "" } }),
+    );
+    expect(errors.baseURL).toBeDefined();
+    expect(errors.model).toBeDefined();
+    expect(
+      isProfileValid(opencode({ opencode: { baseURL: "nope", model: "m" } })),
+    ).toBe(false);
+  });
+  it("a missing opencode config on an openCode profile is invalid", () => {
+    const errors = validateProfile(opencode({ opencode: undefined }));
+    expect(errors.baseURL).toBeDefined();
+    expect(errors.model).toBeDefined();
+  });
+});
+
 describe("defaultInjection", () => {
   it("produces a sensible default per strategy", () => {
     expect(defaultInjection("conventionFile")).toEqual({