refactor(auth): migrate to httpOnly cookies and update vendor listings

Migrated JWT authentication from localStorage to httpOnly cookies using axum-extra. Refactored vendor listing and edit pages to use the centralized API client. Updated schema and data models to support these changes.

schema.sql

@@ -16,7 +16,7 @@ CREATE TABLE service_categories (
     total_companies INTEGER DEFAULT 0
 );
 
-CREATE TABLE companies (
+CREATE TABLE company (
     id SERIAL PRIMARY KEY,
     active BOOLEAN DEFAULT true,
     created DATE NOT NULL DEFAULT CURRENT_DATE,
@@ -31,6 +31,14 @@ CREATE TABLE companies (
     user_id INTEGER
 );
 
+-- Counties (populated by scripts/add_county_to_db.py)
+CREATE TABLE county (
+    id SERIAL PRIMARY KEY,
+    name VARCHAR(255) NOT NULL,
+    state VARCHAR(2) NOT NULL,
+    UNIQUE(name, state)
+);
+
 CREATE TABLE listings (
     id SERIAL PRIMARY KEY,
     company_name VARCHAR(255) NOT NULL,