Let the install set how many steps a run may take

The two limits were compiled in: a task run stopped at
AppData.HarnessMaxToolSteps (200) and a chat reply at
AppData.BotReplyMaxToolSteps (8), so an install that needed a longer task
had to rebuild.

Both are now `app_settings` rows (`harness_max_tool_steps` and
`bot_reply_max_tool_steps`), read at the two loop call sites through
grabHarnessMaxToolSteps and grabReplyMaxToolSteps, and edited by the super
admin on Settings > General beside the prompt appendix. Zero clears a
limit back to the code default, like the bot file quota.

readStepLimit keeps the saved number only when it is a whole number of at
least 1 and no more than AppData.BotStepLimitMax (1000), so a blank, a
zero or a typo falls back instead of stopping every run before its first
turn, and a huge number still ends in the wrap-up report.

runTextLoop keeps AppData.HarnessMaxToolSteps as its default, so it stays
free of database reads and its tests run as they did.

src/pages/admin/settings/general/index.tsx

@@ -1,6 +1,7 @@
 import AppearanceSection from "./(sections)/appearance-section";
 import NotificationsSection from "./(sections)/notifications-section";
 import PromptSection from "./(sections)/prompt-section";
+import RunLimitsSection from "./(sections)/run-limits-section";
 import StorageSection from "./(sections)/storage-section";
 import VersionSection from "./(sections)/version-section";
 import SettingsShell from "../(partials)/settings-shell";
@@ -15,6 +16,7 @@ export default function AdminSettingsGeneralPage() {
             <AppearanceSection />
             <NotificationsSection />
             <PromptSection />
+            <RunLimitsSection />
             <StorageSection />
             <VersionSection />
         </SettingsShell>