Add multi-user auth, admin panel, and timezone support; rename to Yolkbook

- Rename app from Eggtracker to Yolkbook throughout
- Add JWT-based authentication (python-jose, passlib/bcrypt)
- Add users table; all data tables gain user_id FK for full data isolation
- Super admin credentials sourced from ADMIN_USERNAME/ADMIN_PASSWORD env vars,
  synced on every startup; orphaned rows auto-assigned to admin post-migration
- Login page with self-registration; JWT stored in localStorage (30-day expiry)
- Admin panel (/admin): list users, reset passwords, disable/enable, delete,
  and impersonate (Login As) with Return to Admin banner
- Settings modal (gear icon in nav): timezone selector and change password
- Timezone stored per-user; stats date windows computed in user's timezone;
  date input setToday() respects user timezone via Intl API
- migrate_v2.sql for existing single-user installs
- Auto-migration adds timezone column to users on startup
- Updated README with full setup, auth, admin, and migration docs

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

mysql/init.sql

@@ -1,4 +1,4 @@
--- Eggtracker schema
+-- Eggtracker schema — multi-user edition
 -- This file runs automatically on first container startup only.
 -- To re-run it, remove the mysql_data volume: docker compose down -v
 
@@ -8,50 +8,72 @@ CREATE DATABASE IF NOT EXISTS eggtracker
 
 USE eggtracker;
 
+-- ── Users ─────────────────────────────────────────────────────────────────────
+CREATE TABLE IF NOT EXISTS users (
+    id              INT UNSIGNED    NOT NULL AUTO_INCREMENT,
+    username        VARCHAR(64)     NOT NULL,
+    hashed_password VARCHAR(255)    NOT NULL,
+    is_admin        TINYINT(1)      NOT NULL DEFAULT 0,
+    is_disabled     TINYINT(1)      NOT NULL DEFAULT 0,
+    created_at      DATETIME        NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    PRIMARY KEY (id),
+    UNIQUE KEY uq_username (username)
+) ENGINE=InnoDB;
+
 -- ── Egg collections ───────────────────────────────────────────────────────────
 CREATE TABLE IF NOT EXISTS egg_collections (
     id          INT UNSIGNED    NOT NULL AUTO_INCREMENT,
+    user_id     INT UNSIGNED    NOT NULL,
     date        DATE            NOT NULL,
     eggs        INT UNSIGNED    NOT NULL,
     notes       TEXT,
     created_at  DATETIME        NOT NULL DEFAULT CURRENT_TIMESTAMP,
     PRIMARY KEY (id),
-    UNIQUE KEY uq_date (date)
+    UNIQUE KEY uq_user_date (user_id, date),
+    INDEX idx_user_id (user_id),
+    INDEX idx_date (date),
+    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
 ) ENGINE=InnoDB;
 
 -- ── Flock history ─────────────────────────────────────────────────────────────
--- Each row records a change in flock size. The count in effect for any given
--- date is the most recent row with date <= that date.
 CREATE TABLE IF NOT EXISTS flock_history (
     id             INT UNSIGNED    NOT NULL AUTO_INCREMENT,
+    user_id        INT UNSIGNED    NOT NULL,
     date           DATE            NOT NULL,
     chicken_count  INT UNSIGNED    NOT NULL,
     notes          TEXT,
     created_at     DATETIME        NOT NULL DEFAULT CURRENT_TIMESTAMP,
     PRIMARY KEY (id),
-    INDEX idx_date (date)
+    INDEX idx_user_id (user_id),
+    INDEX idx_date (date),
+    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
 ) ENGINE=InnoDB;
 
 -- ── Feed purchases ────────────────────────────────────────────────────────────
 CREATE TABLE IF NOT EXISTS feed_purchases (
     id             INT UNSIGNED      NOT NULL AUTO_INCREMENT,
+    user_id        INT UNSIGNED      NOT NULL,
     date           DATE              NOT NULL,
-    bags           DECIMAL(5, 2)     NOT NULL,   -- decimal for partial bags
+    bags           DECIMAL(5, 2)     NOT NULL,
     price_per_bag  DECIMAL(10, 2)    NOT NULL,
     notes          TEXT,
     created_at     DATETIME          NOT NULL DEFAULT CURRENT_TIMESTAMP,
     PRIMARY KEY (id),
-    INDEX idx_date (date)
+    INDEX idx_user_id (user_id),
+    INDEX idx_date (date),
+    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
 ) ENGINE=InnoDB;
 
 -- ── Other purchases ───────────────────────────────────────────────────────────
--- Catch-all for non-feed costs: bedding, snacks, shelter, etc.
 CREATE TABLE IF NOT EXISTS other_purchases (
     id         INT UNSIGNED   NOT NULL AUTO_INCREMENT,
+    user_id    INT UNSIGNED   NOT NULL,
     date       DATE           NOT NULL,
     total      DECIMAL(10, 2) NOT NULL,
     notes      TEXT,
     created_at DATETIME       NOT NULL DEFAULT CURRENT_TIMESTAMP,
     PRIMARY KEY (id),
-    INDEX idx_date (date)
+    INDEX idx_user_id (user_id),
+    INDEX idx_date (date),
+    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
 ) ENGINE=InnoDB;