perf: server-side caching + remove bulk status fetch from experiment page

- Add backend/src/lib/cache.js — in-process TTL Map cache with
  prefix-based invalidation; no external dependencies

- Cache /experiments/:id/calendar?field=X per (experimentId, field).
  Invalidated immediately on any DailyStatus write.

- Cache /experiments/:id/daily-statuses per (experimentId, date, analysisOnly).
  Invalidated immediately on any DailyStatus write (create/update/delete
  and analysis-summary saves all clear the relevant prefix).

- Add ?analysisOnly=true to /daily-statuses: filters rows where
  analysis_summary IS NOT NULL. Charts are the only consumer and already
  discard rows without analysis data; pre-filtering server-side avoids
  sending the full status payload (71 rows → 1 for this experiment).

- ExperimentCalendar: remove allStatuses prop, fetch calendar data
  directly via API. The component now issues one small GET per field
  selection change instead of the parent loading thousands of rows upfront.

- ExperimentDetail: pass analysisOnly:true to getDailyStatuses;
  drop allStatuses prop from ExperimentCalendar. Cold experiment page
  load no longer fetches every daily status record.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/src/lib/cache.js

@@ -0,0 +1,33 @@
+// Lightweight in-process TTL cache with prefix-based invalidation.
+// Single-process only — suitable for this single-container deployment.
+
+const DEFAULT_TTL_MS = 10 * 60 * 1000; // 10 minutes
+
+const store = new Map(); // key → { value, expiresAt }
+
+function set(key, value, ttlMs = DEFAULT_TTL_MS) {
+  store.set(key, { value, expiresAt: Date.now() + ttlMs });
+}
+
+function get(key) {
+  const entry = store.get(key);
+  if (!entry) return undefined;
+  if (Date.now() > entry.expiresAt) {
+    store.delete(key);
+    return undefined;
+  }
+  return entry.value;
+}
+
+function del(key) {
+  store.delete(key);
+}
+
+// Remove all keys that start with prefix — used to invalidate a whole experiment's worth of cached data.
+function delByPrefix(prefix) {
+  for (const key of store.keys()) {
+    if (key.startsWith(prefix)) store.delete(key);
+  }
+}
+
+module.exports = { set, get, del, delByPrefix };

backend/src/routes/dailyStatuses.js

@@ -1,9 +1,20 @@
 const router = require('express').Router();
 const { body, query } = require('express-validator');
 const prisma = require('../lib/prisma');
+const cache = require('../lib/cache');
 const auditMiddleware = require('../middleware/auditMiddleware');
 const { validateRequest } = require('../middleware/errorHandler');
 
+// Look up which experiment a daily status belongs to, then clear all cached data for it.
+async function invalidateByStatusId(statusId) {
+  const rec = await prisma.dailyStatus.findUnique({
+    where: { id: statusId },
+    select: { animal: { select: { experiment_id: true } } },
+  });
+  const expId = rec?.animal?.experiment_id;
+  if (expId) cache.delByPrefix(`exp:${expId}:`);
+}
+
 const statusValidation = [
   body('animal_id').notEmpty().withMessage('animal_id is required').matches(/^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i).withMessage('animal_id must be a valid UUID'),
   body('date').notEmpty().withMessage('date is required').isISO8601().withMessage('date must be a valid ISO 8601 date (YYYY-MM-DD)'),
@@ -71,6 +82,9 @@ router.post('/', statusValidation, validateRequest, async (req, res, next) => {
     await prisma.auditLog.create({
       data: { table_name: 'daily_statuses', record_id: status.id, action: 'CREATE', changes: { before: null, after: status } },
     });
+    // Invalidate cached experiment data — new status may change calendar counts and chart data
+    const animal = await prisma.animal.findUnique({ where: { id: animal_id }, select: { experiment_id: true } });
+    if (animal) cache.delByPrefix(`exp:${animal.experiment_id}:`);
     res.status(201).json(status);
   } catch (err) { next(err); }
 });
@@ -93,6 +107,7 @@ router.put(
       if (custom_fields !== undefined)           data.custom_fields = custom_fields;
 
       const status = await prisma.dailyStatus.update({ where: { id: req.params.id }, data });
+      await invalidateByStatusId(req.params.id);
       res.json(status);
     } catch (err) { next(err); }
   }
@@ -101,7 +116,10 @@ router.put(
 // PUT /api/daily-statuses/:id/analysis-summary
 router.put('/:id/analysis-summary', async (req, res, next) => {
   try {
-    const status = await prisma.dailyStatus.findUnique({ where: { id: req.params.id } });
+    const status = await prisma.dailyStatus.findUnique({
+      where: { id: req.params.id },
+      include: { animal: { select: { experiment_id: true } } },
+    });
     if (!status) return res.status(404).json({ error: 'Daily status not found' });
 
     const { counts, total, success_rate, source_analysis_id } = req.body;
@@ -121,6 +139,7 @@ router.put('/:id/analysis-summary', async (req, res, next) => {
       where: { id: req.params.id },
       data: { analysis_summary: summary },
     });
+    if (status.animal?.experiment_id) cache.delByPrefix(`exp:${status.animal.experiment_id}:`);
     res.json(updated);
   } catch (err) { next(err); }
 });
@@ -131,7 +150,13 @@ router.delete(
   auditMiddleware('daily_statuses', prisma.dailyStatus),
   async (req, res, next) => {
     try {
+      // Resolve experiment before deleting so we can invalidate after
+      const rec = await prisma.dailyStatus.findUnique({
+        where: { id: req.params.id },
+        select: { animal: { select: { experiment_id: true } } },
+      });
       await prisma.dailyStatus.delete({ where: { id: req.params.id } });
+      if (rec?.animal?.experiment_id) cache.delByPrefix(`exp:${rec.animal.experiment_id}:`);
       res.status(204).send();
     } catch (err) { next(err); }
   }

backend/src/routes/experiments.js

@@ -1,6 +1,7 @@
 const router = require('express').Router();
 const { body } = require('express-validator');
 const prisma = require('../lib/prisma');
+const cache = require('../lib/cache');
 const auditMiddleware = require('../middleware/auditMiddleware');
 const { validateRequest } = require('../middleware/errorHandler');
 const { v4: uuidv4 } = require('uuid');
@@ -311,10 +312,15 @@ router.put('/:id/subject-template', async (req, res, next) => {
 // Returns { field, days: { "YYYY-MM-DD": count } } where count = subjects with non-empty value that day.
 router.get('/:id/calendar', async (req, res, next) => {
   try {
+    const field = req.query.field ?? '';
+    const cacheKey = `exp:${req.params.id}:cal:${field}`;
+
+    const cached = cache.get(cacheKey);
+    if (cached) return res.json(cached);
+
     const exp = await prisma.experiment.findUnique({ where: { id: req.params.id } });
     if (!exp) return res.status(404).json({ error: 'Experiment not found' });
 
-    const field = req.query.field ?? '';
     const BUILTIN_KEYS_SET = new Set(['experiment_description', 'vitals', 'treatment', 'notes']);
     const isBuiltin = BUILTIN_KEYS_SET.has(field);
 
@@ -339,22 +345,37 @@ router.get('/:id/calendar', async (req, res, next) => {
       }
     }
 
-    res.json({ field, days });
+    const result = { field, days };
+    cache.set(cacheKey, result);
+    res.json(result);
   } catch (err) { next(err); }
 });
 
 // GET /api/experiments/:id/daily-statuses  — all statuses for all subjects, analysis_summary included
+// ?date=YYYY-MM-DD  — filter to a single day
+// ?analysisOnly=true  — only return statuses that have a saved analysis_summary (for charts)
 router.get('/:id/daily-statuses', async (req, res, next) => {
   try {
+    const date         = req.query.date ?? '';
+    const analysisOnly = req.query.analysisOnly === 'true';
+    const cacheKey     = `exp:${req.params.id}:ds:${analysisOnly ? '1' : '0'}:${date}`;
+
+    const cached = cache.get(cacheKey);
+    if (cached) return res.json(cached);
+
     const exp = await prisma.experiment.findUnique({ where: { id: req.params.id } });
     if (!exp) return res.status(404).json({ error: 'Experiment not found' });
 
     const where = { animal: { experiment_id: req.params.id } };
-    if (req.query.date) {
-      const d = new Date(req.query.date + 'T00:00:00.000Z');
+    if (date) {
+      const d    = new Date(date + 'T00:00:00.000Z');
       const next = new Date(d); next.setUTCDate(next.getUTCDate() + 1);
       where.date = { gte: d, lt: next };
     }
+    if (analysisOnly) {
+      where.NOT = { analysis_summary: null };
+    }
+
     const statuses = await prisma.dailyStatus.findMany({
       where,
       select: {
@@ -370,6 +391,8 @@ router.get('/:id/daily-statuses', async (req, res, next) => {
       },
       orderBy: { date: 'asc' },
     });
+
+    cache.set(cacheKey, statuses);
     res.json(statuses);
   } catch (err) { next(err); }
 });