Update README, MIGRATION.md, and CLAUDE.md for current feature set

MIGRATION.md

@@ -1,5 +1,81 @@
 # Schema Migrations
 
+## Adding battery metadata fields, device type, and history tables
+
+These columns and tables were added over several feature commits. `create_all()` does not add columns to existing tables, so existing installations need the `ALTER TABLE` commands below. New tables (`capacity_test`, `charge_log`) are created automatically by `create_all()` on next restart for SQLite — the explicit SQL below is provided for reference and for MariaDB operators who manage schema manually.
+
+**Always snapshot first:**
+```bash
+cp batteries.db batteries.db.$(date +%Y-%m-%d).snapshot
+```
+
+**SQLite:**
+```bash
+sqlite3 batteries.db "ALTER TABLE device ADD COLUMN device_type VARCHAR(50);"
+sqlite3 batteries.db "ALTER TABLE battery ADD COLUMN size VARCHAR(20);"
+sqlite3 batteries.db "ALTER TABLE battery ADD COLUMN chemistry VARCHAR(20);"
+sqlite3 batteries.db "ALTER TABLE battery ADD COLUMN capacity_mah INTEGER;"
+sqlite3 batteries.db "ALTER TABLE battery ADD COLUMN tested_capacity_mah INTEGER;"
+sqlite3 batteries.db "ALTER TABLE battery ADD COLUMN tested_date VARCHAR(10);"
+sqlite3 batteries.db "ALTER TABLE battery ADD COLUMN charge_cycles INTEGER;"
+sqlite3 batteries.db "ALTER TABLE battery ADD COLUMN purchase_date VARCHAR(10);"
+sqlite3 batteries.db "ALTER TABLE battery ADD COLUMN storage_location VARCHAR(100);"
+```
+
+New tables (auto-created on restart, shown here for reference):
+```python
+import sqlite3
+conn = sqlite3.connect('batteries.db')
+conn.execute('''CREATE TABLE IF NOT EXISTS capacity_test (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  battery_id INTEGER NOT NULL REFERENCES battery(id) ON DELETE CASCADE,
+  tested_capacity_mah INTEGER NOT NULL,
+  tested_date VARCHAR(10) NOT NULL,
+  notes TEXT
+)''')
+conn.execute('''CREATE TABLE IF NOT EXISTS charge_log (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  battery_id INTEGER NOT NULL REFERENCES battery(id) ON DELETE CASCADE,
+  charged_date VARCHAR(10) NOT NULL,
+  increment_cycles INTEGER NOT NULL DEFAULT 0,
+  notes TEXT
+)''')
+conn.commit(); conn.close()
+```
+
+**MariaDB / MySQL:**
+```sql
+ALTER TABLE device ADD COLUMN device_type VARCHAR(50) NULL;
+ALTER TABLE battery ADD COLUMN size VARCHAR(20) NULL;
+ALTER TABLE battery ADD COLUMN chemistry VARCHAR(20) NULL;
+ALTER TABLE battery ADD COLUMN capacity_mah INT NULL;
+ALTER TABLE battery ADD COLUMN tested_capacity_mah INT NULL;
+ALTER TABLE battery ADD COLUMN tested_date VARCHAR(10) NULL;
+ALTER TABLE battery ADD COLUMN charge_cycles INT NULL;
+ALTER TABLE battery ADD COLUMN purchase_date VARCHAR(10) NULL;
+ALTER TABLE battery ADD COLUMN storage_location VARCHAR(100) NULL;
+
+CREATE TABLE IF NOT EXISTS capacity_test (
+  id INT AUTO_INCREMENT PRIMARY KEY,
+  battery_id INT NOT NULL,
+  tested_capacity_mah INT NOT NULL,
+  tested_date VARCHAR(10) NOT NULL,
+  notes TEXT,
+  CONSTRAINT fk_ct_battery FOREIGN KEY (battery_id) REFERENCES battery(id) ON DELETE CASCADE
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
+
+CREATE TABLE IF NOT EXISTS charge_log (
+  id INT AUTO_INCREMENT PRIMARY KEY,
+  battery_id INT NOT NULL,
+  charged_date VARCHAR(10) NOT NULL,
+  increment_cycles INT NOT NULL DEFAULT 0,
+  notes TEXT,
+  CONSTRAINT fk_cl_battery FOREIGN KEY (battery_id) REFERENCES battery(id) ON DELETE CASCADE
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
+```
+
+---
+
 ## Adding battery_pct_log table
 
 This table was added to track battery percentage change history.