fix: streamline battle reports and casualty details

[prayujt]

Outcome

Keeps battle reports compact and makes losses readable at a glance without turning combat history into a page of freeform text.

What changed

• shows the first three archived combat rounds by default
• adds a Show more control with the remaining round count
• expands the complete round history inside its own bounded scroll area
• provides a Show first 3 rounds control to collapse the log again
• keeps the report header, battle summary, and modal actions fixed around the log
• renders live and archived casualties as compact troop-composition chips
• includes matching visual entries for militia and civilian casualties
• preserves army attribution and visible combat-power context per round
• presents settlement militia as an army-style formation with exact or explicitly concealed strength

Verification

• yarn run check
• yarn eslint src/routes/game/+page.svelte
• yarn run build
• git diff --check