chore: add pre-commit hook with auto-format and lint checks

Pre-commit hook runs prettier --write on staged frontend files, re-stages them, then checks eslint and go vet. Blocks the commit if eslint or vet fails. Stored in .githooks/ (version controlled) — enable with: git config core.hooksPath .githooks

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

.githooks/pre-commit

@@ -0,0 +1,52 @@
+#!/bin/sh
+# Pre-commit hook: run CI-equivalent checks on staged files.
+# Fails the commit if any check fails — matches CI pipeline in .gitea/workflows/ci.yaml.
+#
+# To skip: git commit --no-verify
+
+set -e
+
+RED='\033[0;31m'
+GREEN='\033[0;32m'
+YELLOW='\033[1;33m'
+NC='\033[0m' # No Colour
+
+FAILED=0
+
+# ---------- Frontend (prettier —write, then eslint) ----------
+FRONTEND_FILES=$(git diff --cached --name-only -- 'frontend/' | head -1)
+if [ -n "$FRONTEND_FILES" ]; then
+	printf "${YELLOW}Auto-formatting staged frontend files with prettier...${NC}\n"
+	cd frontend && npx prettier --write . 2>&1
+	# Re-stage any files prettier modified so formatting is included in the commit
+	cd ..
+	git diff --name-only -- 'frontend/' | xargs -r git add
+
+	printf "${YELLOW}Checking eslint...${NC}\n"
+	if ! cd frontend && npx eslint . 2>&1; then
+		printf "${RED}✖ eslint failed${NC}\n"
+		FAILED=1
+	fi
+	cd ..
+fi
+
+# ---------- Backend (go vet) ----------
+BACKEND_FILES=$(git diff --cached --name-only -- 'backend/' | head -1)
+if [ -n "$BACKEND_FILES" ]; then
+	printf "${YELLOW}Checking go vet...${NC}\n"
+	if ! cd backend && go vet ./... 2>&1; then
+		printf "${RED}✖ go vet failed${NC}\n"
+		FAILED=1
+	fi
+	cd ..
+fi
+
+# ---------- Result ----------
+if [ "$FAILED" -ne 0 ]; then
+	printf "\n${RED}Commit blocked — fix the issues above, then commit again.${NC}\n"
+	printf "${YELLOW}To skip checks: git commit --no-verify${NC}\n"
+	exit 1
+fi
+
+printf "${GREEN}✓ All pre-commit checks passed${NC}\n"
+exit 0