Lightweight CRM Template for Lovable

# Context
Build a lightweight CRM for a small team tracking companies, the people at them, and what was
said. The target user is a founder doing their own sales, so speed of entry matters more than
completeness of fields, and nothing should require leaving the keyboard.

## Core Features (Priority Order)
1. Contact list with fast search across name, company and email
2. Contact detail view with a chronological note timeline
3. Add a note in two keystrokes from the contact view, no modal
4. Companies as first-class records, with their contacts listed
5. Ownership: every record has an owner, and the team can see all records
6. A simple pipeline stage on each contact, changed inline from the list

## Visual Style
- Dense list, roomy detail. The list is for scanning, the detail is for reading
- shadcn/ui: Table for the list, Command for search, Badge for stage, Avatar for contacts,
  Textarea for notes, Select for stage changes
- Stage colours consistent between list and detail

## Technical Requirements
- Breakpoints sm 640px, md 768px, lg 1024px; the list becomes cards below md
- Search filters client-side against loaded rows for instant feedback, then falls back to a
  server query when the term is longer than the loaded page
- Optimistic update on a stage change, reverted on failure with a visible message
- Empty states for no contacts, no search results and no notes, each different
- Dark mode via Tailwind's dark: prefix

## Implementation Strategy
1. The schema from schema.sql and the contact list read
2. Contact detail and the note timeline
3. Note creation, with the optimistic path and the failure path
4. Companies, then the company-to-contact relationship
5. Pipeline stage last, because it changes the list and the detail together

## Safe-Guard Instructions
- Ownership is server-derived from auth.uid(). Never accept an owner id from the client.
- A note is append-only in the UI even though the schema allows the author to edit their own.
  Do not add bulk delete.
- Do not add a policy that lets a user reassign another user's records.

## Growth Features (Required for Distribution)
- **B2B Sales:** make one contact view shareable as a read-only summary, so a colleague can
  see the history without an account, and make it obvious when a share link is active.

-- Lightweight CRM schema for Lovable + Supabase
-- Reviewed row-level security. Read the comments before running this.
--
-- Model choice worth understanding: this is a SHARED team CRM. Every authenticated user can
-- read every record, because a sales team that cannot see each other's pipeline is not
-- useful. Writes are restricted to the owner. If you need per-user isolation instead, change
-- the select policies to owner_id = auth.uid() and re-run the verification queries.

create type public.pipeline_stage as enum
  ('new', 'contacted', 'qualified', 'proposal', 'won', 'lost');

create table public.companies (

-- Verification queries. Run these as user A, then sign in as user B and repeat 3 and 4.

-- 1. Should return the whole team's contacts. This schema is deliberately shared.
select id, full_name, stage, owner_id from public.contacts limit 20;

-- 2. Should SUCCEED, and owner_id should default to you without being supplied.
insert into public.contacts (full_name, email) values ('Verify Person', 'v@example.com');
select full_name, owner_id = auth.uid() as owned_by_me
from public.contacts where email = 'v@example.com';

-- As user B, against a contact owned by user A: