Lesson 5.5 · 55 minFollow-up tasks and reminders

Add follow-up tasks to the CRM and build the Today page.

Purpose: the owner must see, every day, whom to contact, and no open lead
should be left without a next step.

Context: docs/crm-spec.md, the lead_tasks table, the lead card and admin
layout from earlier lessons.

Lead card: a new "Tasks" section. Add a task with a title and a due date
(default: tomorrow). List this lead's tasks: open ones first, by due date;
done ones below with the completion time. Open tasks have a "Done" checkbox.

Today page at /admin/today, replacing the placeholder:
- two groups: "Overdue" (due date before today, not done), oldest first,
  and "Due today" (due date equals today, not done);
- "today" is the current date in the business time zone from the spec;
- each row: the task title, the lead's name linking to the lead card, the
  status badge, the due date, the Call button if the lead has a phone, and
  a "Done" checkbox;
- ticking "Done" records the completion time and then asks "What is the
  next step?" with a title, a due date and a "No next step" choice;
- when nothing is due: a clear "Nothing due today" message;
- the sidebar link "Today" shows the number of due plus overdue tasks.

Constraints: server-side reads and writes for the signed-in owner only. No
new libraries without asking.

Before you report, verify in a real browser using the browser connection;
when the login page appears, wait while I sign in myself. Check and report
on each: tasks due today, yesterday and tomorrow on a sample lead appear
under "Due today", under "Overdue", and only on the lead card; ticking one
done and creating a next step removes the old task from Today and adds the
new one to the lead card; the sidebar count is right; everything survives
a reload and is in lead_tasks; phone width. Run the build. Say what you
could not verify.

Add a daily summary of follow-up tasks, sent automatically every morning.

Purpose: the owner is told whom to contact today even without opening the
CRM.

Context: the project is hosted on Vercel. First read Vercel's current Cron
Jobs documentation and follow it; tell me which pages you read. The code
from lesson 4.5 already sends Telegram messages and email. CRON_SECRET is
already in .env.local and in the Vercel project. Never print its value.

Build:
- an endpoint at /api/cron/daily-summary that answers GET requests. It
  first checks that the Authorization header equals "Bearer " plus
  CRON_SECRET; if the variable is missing or the header does not match, it
  returns 401 and does nothing else;
- it finds open tasks that are overdue or due today, using exactly the same
  definition and time zone as the Today page (share the code, do not copy
  it). There is no signed-in user here, so read the database with the
  server-only secret access set up in section 4, which must never reach the
  browser; tell me which existing server code you reused for this;
- it sends one message through Telegram, reusing the existing sending code:
  the date, the counts, then each task as "lead name — task title", overdue
  first, each with a link to its lead card on the production domain. No
  phone numbers or emails. If nothing is due: "No follow-ups due today";
- it returns the counts only;
- a vercel.json entry that schedules this path once a day at 07:00 UTC.

Constraints: one run per day at most. If sending fails, return an error
status so the failure shows in Vercel's logs.

Verify before you report: with the local site running, call the endpoint
without the header and confirm 401; call it with the header, taking the
value from .env.local without displaying it, and confirm success; tell me
the counts so I can compare them with the Today page and the message I
receive. Open the Today page in the browser and compare too. Run the build.