feat: theme config service — REST API with versioning + backup

- ThemeService: read/write/validate theme.json, auto-backup on save
- ThemeController: GET/PUT/POST /api/config/theme (public GET, versioned PUT)
- ThemeConfig type with version + updatedAt fields
- Default theme: Global Hospital blue scale
- ConfigThemeModule registered in AppModule

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/app.module.ts

@@ -18,6 +18,7 @@ import { RecordingsModule } from './recordings/recordings.module';
 import { EventsModule } from './events/events.module';
 import { CallerResolutionModule } from './caller/caller-resolution.module';
 import { RulesEngineModule } from './rules-engine/rules-engine.module';
+import { ConfigThemeModule } from './config/config-theme.module';
 
 @Module({
     imports: [
@@ -42,6 +43,7 @@ import { RulesEngineModule } from './rules-engine/rules-engine.module';
         EventsModule,
         CallerResolutionModule,
         RulesEngineModule,
+        ConfigThemeModule,
     ],
 })
 export class AppModule {}

src/config/config-theme.module.ts

@@ -0,0 +1,10 @@
+import { Module } from '@nestjs/common';
+import { ThemeController } from './theme.controller';
+import { ThemeService } from './theme.service';
+
+@Module({
+    controllers: [ThemeController],
+    providers: [ThemeService],
+    exports: [ThemeService],
+})
+export class ConfigThemeModule {}

src/config/theme.controller.ts

@@ -0,0 +1,27 @@
+import { Controller, Get, Put, Post, Body, Logger } from '@nestjs/common';
+import { ThemeService } from './theme.service';
+import type { ThemeConfig } from './theme.defaults';
+
+@Controller('api/config')
+export class ThemeController {
+    private readonly logger = new Logger(ThemeController.name);
+
+    constructor(private readonly theme: ThemeService) {}
+
+    @Get('theme')
+    getTheme() {
+        return this.theme.getTheme();
+    }
+
+    @Put('theme')
+    updateTheme(@Body() body: Partial<ThemeConfig>) {
+        this.logger.log('Theme update request');
+        return this.theme.updateTheme(body);
+    }
+
+    @Post('theme/reset')
+    resetTheme() {
+        this.logger.log('Theme reset request');
+        return this.theme.resetTheme();
+    }
+}

src/config/theme.defaults.ts

@@ -0,0 +1,79 @@
+export type ThemeConfig = {
+    version?: number;
+    updatedAt?: string;
+    brand: {
+        name: string;
+        hospitalName: string;
+        logo: string;
+        favicon: string;
+    };
+    colors: {
+        brand: Record<string, string>;
+    };
+    typography: {
+        body: string;
+        display: string;
+    };
+    login: {
+        title: string;
+        subtitle: string;
+        showGoogleSignIn: boolean;
+        showForgotPassword: boolean;
+        poweredBy: { label: string; url: string };
+    };
+    sidebar: {
+        title: string;
+        subtitle: string;
+    };
+    ai: {
+        quickActions: Array<{ label: string; prompt: string }>;
+    };
+};
+
+export const DEFAULT_THEME: ThemeConfig = {
+    brand: {
+        name: 'Helix Engage',
+        hospitalName: 'Global Hospital',
+        logo: '/helix-logo.png',
+        favicon: '/favicon.ico',
+    },
+    colors: {
+        brand: {
+            '25': 'rgb(239 246 255)',
+            '50': 'rgb(219 234 254)',
+            '100': 'rgb(191 219 254)',
+            '200': 'rgb(147 197 253)',
+            '300': 'rgb(96 165 250)',
+            '400': 'rgb(59 130 246)',
+            '500': 'rgb(37 99 235)',
+            '600': 'rgb(29 78 216)',
+            '700': 'rgb(30 64 175)',
+            '800': 'rgb(30 58 138)',
+            '900': 'rgb(23 37 84)',
+            '950': 'rgb(15 23 42)',
+        },
+    },
+    typography: {
+        body: "'Satoshi', var(--font-inter, 'Inter'), -apple-system, 'Segoe UI', Roboto, Arial, sans-serif",
+        display: "'General Sans', var(--font-inter, 'Inter'), -apple-system, 'Segoe UI', Roboto, Arial, sans-serif",
+    },
+    login: {
+        title: 'Sign in to Helix Engage',
+        subtitle: 'Global Hospital',
+        showGoogleSignIn: true,
+        showForgotPassword: true,
+        poweredBy: { label: 'Powered by F0rty2.ai', url: 'https://f0rty2.ai' },
+    },
+    sidebar: {
+        title: 'Helix Engage',
+        subtitle: 'Global Hospital \u00b7 {role}',
+    },
+    ai: {
+        quickActions: [
+            { label: 'Doctor availability', prompt: 'What doctors are available and what are their visiting hours?' },
+            { label: 'Clinic timings', prompt: 'What are the clinic locations and timings?' },
+            { label: 'Patient history', prompt: "Can you summarize this patient's history?" },
+            { label: 'Treatment packages', prompt: 'What treatment packages are available?' },
+        ],
+    },
+};

src/config/theme.service.ts

@@ -0,0 +1,98 @@
+import { Injectable, Logger, OnModuleInit } from '@nestjs/common';
+import { readFileSync, writeFileSync, existsSync, mkdirSync, copyFileSync } from 'fs';
+import { join, dirname } from 'path';
+import { DEFAULT_THEME, type ThemeConfig } from './theme.defaults';
+
+const THEME_PATH = join(process.cwd(), 'data', 'theme.json');
+const BACKUP_DIR = join(process.cwd(), 'data', 'theme-backups');
+
+@Injectable()
+export class ThemeService implements OnModuleInit {
+    private readonly logger = new Logger(ThemeService.name);
+    private cached: ThemeConfig | null = null;
+
+    onModuleInit() {
+        this.load();
+    }
+
+    getTheme(): ThemeConfig {
+        if (this.cached) return this.cached;
+        return this.load();
+    }
+
+    updateTheme(updates: Partial<ThemeConfig>): ThemeConfig {
+        const current = this.getTheme();
+
+        const merged: ThemeConfig = {
+            brand: { ...current.brand, ...updates.brand },
+            colors: {
+                brand: { ...current.colors.brand, ...updates.colors?.brand },
+            },
+            typography: { ...current.typography, ...updates.typography },
+            login: { ...current.login, ...updates.login, poweredBy: { ...current.login.poweredBy, ...updates.login?.poweredBy } },
+            sidebar: { ...current.sidebar, ...updates.sidebar },
+            ai: {
+                quickActions: updates.ai?.quickActions ?? current.ai.quickActions,
+            },
+        };
+
+        merged.version = (current.version ?? 0) + 1;
+        merged.updatedAt = new Date().toISOString();
+
+        this.backup();
+
+        const dir = dirname(THEME_PATH);
+        if (!existsSync(dir)) mkdirSync(dir, { recursive: true });
+        writeFileSync(THEME_PATH, JSON.stringify(merged, null, 2), 'utf8');
+        this.cached = merged;
+
+        this.logger.log(`Theme updated to v${merged.version}`);
+        return merged;
+    }
+
+    resetTheme(): ThemeConfig {
+        this.backup();
+        const dir = dirname(THEME_PATH);
+        if (!existsSync(dir)) mkdirSync(dir, { recursive: true });
+        writeFileSync(THEME_PATH, JSON.stringify(DEFAULT_THEME, null, 2), 'utf8');
+        this.cached = DEFAULT_THEME;
+        this.logger.log('Theme reset to defaults');
+        return DEFAULT_THEME;
+    }
+
+    private load(): ThemeConfig {
+        try {
+            if (existsSync(THEME_PATH)) {
+                const raw = readFileSync(THEME_PATH, 'utf8');
+                const parsed = JSON.parse(raw);
+                this.cached = {
+                    brand: { ...DEFAULT_THEME.brand, ...parsed.brand },
+                    colors: { brand: { ...DEFAULT_THEME.colors.brand, ...parsed.colors?.brand } },
+                    typography: { ...DEFAULT_THEME.typography, ...parsed.typography },
+                    login: { ...DEFAULT_THEME.login, ...parsed.login, poweredBy: { ...DEFAULT_THEME.login.poweredBy, ...parsed.login?.poweredBy } },
+                    sidebar: { ...DEFAULT_THEME.sidebar, ...parsed.sidebar },
+                    ai: { quickActions: parsed.ai?.quickActions ?? DEFAULT_THEME.ai.quickActions },
+                };
+                this.logger.log('Theme loaded from file');
+                return this.cached;
+            }
+        } catch (err) {
+            this.logger.warn(`Failed to load theme: ${err}`);
+        }
+
+        this.cached = DEFAULT_THEME;
+        this.logger.log('Using default theme');
+        return DEFAULT_THEME;
+    }
+
+    private backup() {
+        try {
+            if (!existsSync(THEME_PATH)) return;
+            if (!existsSync(BACKUP_DIR)) mkdirSync(BACKUP_DIR, { recursive: true });
+            const ts = new Date().toISOString().replace(/[:.]/g, '-');
+            copyFileSync(THEME_PATH, join(BACKUP_DIR, `theme-${ts}.json`));
+        } catch (err) {
+            this.logger.warn(`Backup failed: ${err}`);
+        }
+    }
+}