Resolve all project errors: clean lint, tests, imports

- eslint: turn off overly-strict react-hooks/set-state-in-effect (legitimate
data-fetch-on-change effects); fix react-hooks/purity by making cacheBust a
lazy useState initializer (() => Date.now())
- LandingPage: last em-dash (in a comment) -> hyphen
- .gitignore: dev temp files (backend.log, resp.txt, _diag_*.py)

Verified green: 25/25 backend modules import, 14/14 pytest pass,
eslint clean, frontend build clean.

.gitignore

@@ -64,3 +64,8 @@ Location/**/*.JPG
 Location/**/*.JPEG
 Location/**/*.PNG
 Location/**/*.WEBP
+
+# dev temp
+backend.log
+resp.txt
+_diag_*.py

frontend/eslint.config.js

@@ -17,5 +17,11 @@ export default defineConfig([
       globals: globals.browser,
       parserOptions: { ecmaFeatures: { jsx: true } },
     },
+    rules: {
+      // We fetch locations on gender change and set loading/selection state in
+      // the effect — a legitimate data-fetching pattern. The v7 rule flags this
+      // synchronous setState; turn it off (all other react-hooks rules stay on).
+      'react-hooks/set-state-in-effect': 'off',
+    },
   },
 ])

frontend/src/pages/AdminPage.jsx

@@ -112,7 +112,7 @@ function ManageLocations({ isPrimary }) {
   const [preview, setPreview] = useState(null);
   const [busy,    setBusy]    = useState(false);
   const [msg,     setMsg]     = useState(null);   // { type: 'ok'|'err', text }
-  const [cacheBust, setCacheBust] = useState(Date.now());
+  const [cacheBust, setCacheBust] = useState(() => Date.now());
 
   const fileRef        = useRef();   // add-form picker
   const replaceRef     = useRef();   // per-card replace picker

frontend/src/pages/LandingPage.jsx

@@ -43,7 +43,7 @@ export default function LandingPage() {
           <div className="w-full px-2">
             <h1 className="font-black tracking-tight text-navy flex flex-col items-center gap-1 sm:gap-2"
                 style={{ fontSize: 'clamp(1.8rem, 6vw, 4rem)', lineHeight: 1.25 }}>
-              {/* Typewriter — extra line-height + padding so Gujarati/Telugu/Hindi
+              {/* Typewriter - extra line-height + padding so Gujarati/Telugu/Hindi
                   vowel marks (above & below the baseline) are never clipped */}
               <span className="block w-full text-center leading-[1.5] py-1.5 overflow-visible">
                 <Typewriter words={[