feat(ui): allow filtering by dedicated channel cases

[whitdog47]

This PR adds the ability to filter cases by "security events only," which shows cases that have a dedicated channel by filtering for cases that do NOT have signal instances attached.

• Added a new boolean filter security_event_only to the case filtering system
• Updated the frontend UI to include a checkbox for enabling this filter
• Modified backend filtering logic to handle the new boolean parameter

[Copilot]

Pull Request Overview

This PR implements a new filtering capability for cases to show only "security events" - cases with dedicated channels that do not have signal instances attached.

• Added boolean filter security_event_only to frontend and backend filtering systems
• Modified UI to include a checkbox for enabling the security events filter
• Updated backend query logic to filter cases without signal instances using NOT EXISTS

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/dispatch/static/dispatch/src/search/utils.js	Added boolean filter handling to extract and pass security_event_only parameter
src/dispatch/static/dispatch/src/router/utils.js	Added boolean value processing for URL parameter handling
src/dispatch/static/dispatch/src/case/store.js	Added security_event_only field to default filter state
src/dispatch/static/dispatch/src/case/TableFilterDialog.vue	Added UI checkbox and state management for security events filter
src/dispatch/database/service.py	Added backend parameter handling and NOT EXISTS query logic

Comments suppressed due to low confidence (1)

src/dispatch/static/dispatch/src/case/TableFilterDialog.vue:1

• The card subtitle and checkbox hint have contradictory information. The subtitle says 'dedicated channel' while the hint says 'signal instances attached', but the backend logic filters for cases WITHOUT signal instances.

<template>

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}