Mark system health checks as completed in ROADMAP.md (v2.3.1)

[Copilot]

The ROADMAP.md incorrectly listed system health checks as incomplete under "Logging & Monitoring". This feature was fully implemented in v2.3.1 with the About page, which includes M3U/XMLTV status checks, EPG freshness monitoring (6-hour threshold), and active tuner display.

Changes

• Updated line 25 in ROADMAP.md to mark system health checks as completed
• Added version annotation *(v2.3.1)* to match formatting of other completed items

-- [ ] Add system health checks (tuner reachability, XMLTV freshness).
+- [x] Add system health checks (tuner reachability, XMLTV freshness). *(v2.3.1)*

Original prompt

Problem Statement

The ROADMAP.md file currently shows "Add system health checks (tuner reachability, XMLTV freshness)" as an incomplete feature under section 2 (Logging & Monitoring). However, this feature was actually completed in v2.3.1 (released 2025-09-26).

The system health feature is fully implemented in templates/about.html and includes:

• M3U Playlist status checks
• XMLTV File status checks
• EPG Freshness checks (with 6-hour threshold)
• Active Tuner display
• Detailed diagnostics section

Required Changes

Update ROADMAP.md to mark the system health checks feature as completed:

Current line (approximately line 25):

- [ ] Add system health checks (tuner reachability, XMLTV freshness).

Should be changed to:

- [x] Add system health checks (tuner reachability, XMLTV freshness). *(v2.3.1)*

Context

The feature was implemented in commit 3f3e18e as part of v2.3.1, which added the About page with dynamic system health monitoring including M3U playlist validation, XMLTV file checks, and EPG freshness monitoring.

Acceptance Criteria

• The system health checks line in ROADMAP.md is marked with [x]
• The version number (v2.3.1) is added after the feature description
• The formatting matches other completed items in the roadmap (e.g., line 24: "Add filtering and pagination in logs view. (v4.5.0)")

This pull request was created from Copilot chat.

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