Commits of agents carry a co-author trailer naming the model

A git wrapper (docker/git-coauthor -> /usr/local/lib/codecraft/bin/git) adds
--trailer "$CODECRAFT_COMMIT_TRAILER" right after the commit subcommand; the
agent shell puts it first on PATH and sets the trailer in the script itself
(works inside the sandbox, which clears the environment). Default text:
"Co-Authored-By: {model} ({provider}) via CodeCraft" (server.commit_trailer,
Settings -> General; empty = off). Git skips duplicates (amend, model wrote it).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/src/components/Settings.tsx

@@ -248,6 +248,7 @@ function General({ cfg, reload }: { cfg: ConfigResponse; reload: () => void }) {
     small_model: s.small_model ?? "",
     currency: s.currency ?? "USD",
     auto_compact_threshold: s.auto_compact_threshold ?? 0.85,
+    commit_trailer: ((s as any).commit_trailer ?? "Co-Authored-By: {model} ({provider}) via CodeCraft") as string,
     max_parallel_subagents: s.max_parallel_subagents ?? 4,
     monthly_budget: s.monthly_budget ?? 0,
     budget_warning: s.budget_warning ?? 0.8,
@@ -271,6 +272,7 @@ function General({ cfg, reload }: { cfg: ConfigResponse; reload: () => void }) {
         { path: ["server", "small_model"], value: form.small_model },
         { path: ["server", "currency"], value: form.currency },
         { path: ["server", "auto_compact_threshold"], value: Number(form.auto_compact_threshold) },
+        { path: ["server", "commit_trailer"], value: form.commit_trailer.trim() },
         { path: ["server", "max_parallel_subagents"], value: Number(form.max_parallel_subagents) },
         { path: ["server", "monthly_budget"], value: Number(form.monthly_budget) || 0 },
         { path: ["server", "budget_warning"], value: Number(form.budget_warning) || 0.8 },
@@ -305,6 +307,9 @@ function General({ cfg, reload }: { cfg: ConfigResponse; reload: () => void }) {
           <label>{t("settings.autoCompact")}</label>
           <input type="number" min={0} max={1} step={0.05} value={form.auto_compact_threshold} onChange={(e) => setForm({ ...form, auto_compact_threshold: e.target.value })} />
           <div className="hint">{t("settings.autoCompactHint")}</div>
+          <label>{t("settings.commitTrailer")}</label>
+          <input className="mono" value={form.commit_trailer} placeholder={t("settings.commitTrailerOff")} onChange={(e) => setForm({ ...form, commit_trailer: e.target.value })} />
+          <div className="hint">{t("settings.commitTrailerHint")}</div>
           <label>{t("settings.monthlyBudgetTotal")}</label>
           <input type="number" min={0} value={form.monthly_budget} onChange={(e) => setForm({ ...form, monthly_budget: e.target.value })} />
           <div className="hint">{t("settings.monthlyBudgetHint")}</div>