Add uploaded_by and description fields to notification rules

Description

The rules table has "Uploaded By" and "Description" columns that display "-" placeholders. The backend Rule struct doesn't have these fields yet, so the frontend can't show real values.

Acceptance Criteria

• Rule struct in rule_structs.rs has uploaded_by and description fields
• add_rule persists both fields; uploaded_by is set from client identity automatically
• get_all_rules and get_all_rules_with_client_info return both fields
• Frontend table columns display real values instead of "-"
• Add Rule dialog includes a description input
• Edit Rule dialog allows editing description

Proposed Solution

Add optional String fields to the Rule struct and RulePayload in rule_structs.rs. Update add_rule in rule_controller.rs to populate uploaded_by by an optionally client set name on the Notification Rule page or by default the client identifier. On the frontend, update rules.api.ts types, the add/edit dialog forms, and remove the "-" hardcodes in rules-table.component.html.

Start with Rule and RulePayload in rule_structs.rs, then trace add_rule, get_all_rules, and get_all_rules_with_client_info in rule_controller.rs. Update the types in rules.api.ts and the add/edit dialogs, then replace the placeholders in rules-table.component.html. Done means both fields persist and return from the backend, uploaded_by uses client identity, and the dialogs and table display the values.