Integrate the themed TSC dashboard with SIC

[Tylevo]

SIC now lists Tactical Services Control under Mod pages and opens the existing TerraGroup dashboard. Its colors, service cards, typography, and controls are retained, with sidebar links back to SIC and Config Editor.

The native editor now separates Apply to Runtime, Save to Disk, and Load Disk. Dashboard and SIC sessions share revision protection, and each native editor registration owns its snapshot. Config writes use atomic replacement with bounded retries for brief Windows file locks. Failed saves retain the active settings; the dashboard keeps its draft and warns before discarding unsaved edits.

This is the 1.3.9 source candidate for SPT 4.1.4. The README keeps v1.3.8 as the current public download. No release assets or player state are changed by this PR. Fika remains explicitly untested on the current SPT/Fika versions.

Validation:

• Full local solution build: all four runtime assemblies, zero errors, four existing warnings, deployment disabled.
• 238 C# regression checks and seven dashboard interaction tests passed.
• 14 integration checks passed through SPT 4.1.4's actual ConfigEditorService.
• 13 isolated running-server HTTP checks passed, including the SIC home link, exact dashboard files, valid saves, stale conflicts, and disk reloads.
• Theme preserved by source diff. Desktop visual verification stopped because computer-use could not reliably determine the active browser URL; visual launcher acceptance remains open.

See docs/validation/v1.3.9.md for scope and limitations.