Remove architecture diagrams from README

They were overloading the document. Reverts the beautiful-mermaid
diagrams added in 722bd6c.

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

README.md

@@ -33,104 +33,6 @@ A self-hosted, multi-company budget and project tracking tool built for internal
 
 ---
 
-## Architecture
-
-Diagrams use [Mermaid](https://mermaid.js.org/) and are designed to render cleanly through [beautiful-mermaid](https://github.com/lukilabs/beautiful-mermaid) (tokyo-night theme).
-
-### System Overview
-
-```mermaid
-%%{init: {'theme':'dark', 'themeVariables': {'primaryColor':'#7aa2f7','lineColor':'#3d59a1','background':'#1a1b26'}}}%%
-flowchart LR
-    U[User Browser] -->|HTTPS| N[nginx reverse proxy]
-    N -->|127.0.0.1:3000| A[SvelteKit Node app]
-    A --> DB[(PostgreSQL)]
-    A -.optional.-> O[OIDC Provider]
-    subgraph Proxmox VM
-        N
-        A
-        DB
-    end
-```
-
-### Data Model
-
-```mermaid
-%%{init: {'theme':'dark', 'themeVariables': {'primaryColor':'#7aa2f7','lineColor':'#3d59a1','background':'#1a1b26'}}}%%
-erDiagram
-    users ||--o{ sessions : has
-    users ||--o{ company_members : "belongs to"
-    companies ||--o{ company_members : has
-    companies ||--o{ projects : contains
-    companies ||--o{ categories : defines
-    companies ||--o{ tags : defines
-    companies ||--o{ budget_allocations : tracks
-    companies ||--o{ company_log : audits
-    projects ||--o{ expenses : contains
-    projects ||--o{ budget_allocations : receives
-    categories ||--o{ expenses : classifies
-    expenses ||--o{ expense_tags : has
-    tags ||--o{ expense_tags : tagged
-    users ||--o{ expenses : "submits / approves"
-
-    users {
-        text id PK
-        text email UK
-        text password_hash
-        text oidc_subject
-        bool is_system_admin
-        timestamp disabled_at
-    }
-    companies {
-        uuid id PK
-        text name
-        numeric total_budget
-        text currency
-        timestamp deleted_at
-    }
-    company_members {
-        uuid id PK
-        text user_id FK
-        uuid company_id FK
-        enum role "admin|manager|user|viewer"
-    }
-    projects {
-        uuid id PK
-        uuid company_id FK
-        numeric allocated_budget
-    }
-    expenses {
-        uuid id PK
-        uuid project_id FK
-        numeric amount
-        enum status "pending|approved|rejected"
-    }
-```
-
-### Expense Approval Flow
-
-```mermaid
-%%{init: {'theme':'dark', 'themeVariables': {'primaryColor':'#7aa2f7','lineColor':'#3d59a1','background':'#1a1b26'}}}%%
-sequenceDiagram
-    actor U as User
-    actor M as Manager
-    participant A as SvelteKit
-    participant DB as PostgreSQL
-    participant L as Audit Log
-
-    U->>A: POST /projects/:id/expenses/new
-    A->>DB: INSERT expense (status=pending)
-    A->>L: log expense_submitted
-    A-->>U: 302 redirect
-    Note over M: Reviews pending queue
-    M->>A: POST /expenses/:id approve
-    A->>DB: UPDATE status=approved
-    A->>L: log expense_approved
-    A-->>M: success
-```
-
----
-
 ## Prerequisites
 
 - Node.js 20 or later