Make the skill runbook limits a general setting

The longest runbook a skill may save and how much of it load_skill hands
back are now set on Settings > General (skill_body_max_chars,
skill_body_shown_chars), defaulting to AppData.SkillBodyMaxChars and
SkillBodyShownChars. Saving, confirming and proposing a skill check the
install's limit; a skill saved before it was lowered can still be toggled.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/functions/backend/db/app-settings/grab-skill-limits.ts

@@ -0,0 +1,53 @@
+import { AppData } from "@/src/data/app-data";
+import { SkillBodyMaxCharsSettingKey, SkillBodyShownCharsSettingKey } from "@/src/dict/skill-dict";
+import readStepLimit from "@/src/utils/read-step-limit";
+import type { SkillLimitsOverview } from "@/src/types";
+import grabAppSetting from "./grab-app-setting";
+
+/**
+ * The longest runbook a skill may save: the install's own limit
+ * (`skill_body_max_chars`, Settings > General), else
+ * `AppData.SkillBodyMaxChars`.
+ */
+export async function grabSkillBodyMaxChars() {
+    return readStepLimit({
+        saved: await grabAppSetting({ key: SkillBodyMaxCharsSettingKey }),
+        fallback: AppData.SkillBodyMaxChars,
+        max: AppData.SkillBodyLimitMax,
+    });
+}
+
+/**
+ * How much of a runbook `load_skill` hands back in one call: the install's
+ * own limit (`skill_body_shown_chars`, Settings > General), else
+ * `AppData.SkillBodyShownChars`.
+ */
+export async function grabSkillBodyShownChars() {
+    return readStepLimit({
+        saved: await grabAppSetting({ key: SkillBodyShownCharsSettingKey }),
+        fallback: AppData.SkillBodyShownChars,
+        max: AppData.SkillBodyLimitMax,
+    });
+}
+
+/**
+ * Both limits with their defaults, for the settings pages.
+ */
+export default async function grabSkillLimitsOverview() {
+    const [body_max_chars, body_shown_chars] = await Promise.all([
+        grabSkillBodyMaxChars(),
+        grabSkillBodyShownChars(),
+    ]);
+
+    const overview: SkillLimitsOverview = {
+        body_max_chars,
+        body_shown_chars,
+        body_max_default: AppData.SkillBodyMaxChars,
+        body_shown_default: AppData.SkillBodyShownChars,
+        max: AppData.SkillBodyLimitMax,
+    };
+
+    return overview;
+}
+
+export type { SkillLimitsOverview };