feat: add prek pre-commit hooks and dependabot (#1720)

* feat: add prek pre-commit hooks and dependabot

Pre-commit hooks (via prek):
- Basic hygiene: trailing-whitespace, end-of-file-fixer, check-yaml, check-added-large-files, check-merge-conflict
- Security: detect-secrets, zizmor (GitHub Actions audit)
- Linting: shellcheck, actionlint, oxlint, swiftlint
- Formatting: oxfmt, swiftformat

Dependabot:
- npm and GitHub Actions ecosystems
- Grouped updates (production/development/actions)
- 7-day cooldown for supply chain protection

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* docs: add prek install instruction to AGENTS.md

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

extensions/mattermost/src/group-mentions.ts

@@ -11,4 +11,4 @@ export function resolveMattermostGroupRequireMention(
   });
   if (typeof account.requireMention === "boolean") return account.requireMention;
   return true;
-}
+}

extensions/mattermost/src/mattermost/accounts.ts

@@ -112,4 +112,4 @@ export function listEnabledMattermostAccounts(cfg: ClawdbotConfig): ResolvedMatt
   return listMattermostAccountIds(cfg)
     .map((accountId) => resolveMattermostAccount({ cfg, accountId }))
     .filter((account) => account.enabled);
-}
+}

extensions/mattermost/src/mattermost/client.ts

@@ -205,4 +205,4 @@ export async function uploadMattermostFile(
     throw new Error("Mattermost file upload failed");
   }
   return info;
-}
+}

extensions/mattermost/src/mattermost/monitor-helpers.ts

@@ -147,4 +147,4 @@ export function resolveThreadSessionKeys(params: {
     ? `${params.baseSessionKey}:thread:${threadId}`
     : params.baseSessionKey;
   return { sessionKey, parentSessionKey: params.parentSessionKey };
-}
+}

extensions/mattermost/src/mattermost/probe.ts

@@ -67,4 +67,4 @@ export async function probeMattermost(
   } finally {
     if (timer) clearTimeout(timer);
   }
-}
+}

extensions/mattermost/src/onboarding-helpers.ts

@@ -39,4 +39,4 @@ export async function promptAccountId(params: PromptAccountIdParams): Promise<st
     );
   }
   return normalized;
-}
+}

extensions/mattermost/src/onboarding.ts

@@ -184,4 +184,4 @@ export const mattermostOnboardingAdapter: ChannelOnboardingAdapter = {
       mattermost: { ...cfg.channels?.mattermost, enabled: false },
     },
   }),
-};
+};