feat: revamp city training and battlefield UI

[prayujt]

Outcome

Makes troop training a barracks interaction backed by the city-wide queue, gives active combat clearer map and detail treatments, exposes observable casualties in real time, and lets players name their armies.

City training

• Keeps the navbar Training tab as a read-only per-city overview.
• Shows each city name, barracks lane levels/speeds, and upcoming queue.
• Adds a Go to training action that centers a barracks and opens its management view.
• Makes every barracks in a city expose the same shared training workspace.
• Moves troop selection, batch sizing, costs, population reservation, and submission into that workspace.
• Shows active batches only on assigned lanes; the queue contains only upcoming batches.
• Allows full-refund cancellation of upcoming batches.
• Prioritizes Recruitable and Militia in the barracks population summary instead of duplicating the full City Management chart.
• Anchors active training badges to their barracks and gives troop types distinct accents.
• Links to City/Town Policy and labels every unowned building action as View details.
• Gives the training panel more width and independent scrolling.

Battlefield clarity

• Removes duplicated per-army battle badges.
• Adds one compact red, text-free crossed-swords marker per active battle.
• Makes battle markers directly open the battle details dialog.
• Marks besieged settlement centers with a pulsing red perimeter without an oversized banner.
• Adds amber pulsing territory boundaries, a center ring, and an occupation flag during occupation.
• Drives the five-second countdown and progress width from the same server timestamp on a 250ms display clock.
• Shows completed rounds, cumulative casualties, and latest-round casualties for both sides.
• Shows troop-type, militia, and civilian losses while keeping undisclosed enemy starting/surviving strength hidden.
• Carries the same public-casualty/private-strength model into mailbox battle reports.
• Honors reduced-motion preferences and uses the game custom action cursor.

Army names

• Uses persistent army names in the army list, inspector, orders, battle dialog, and mailbox reports.
• Adds an inline rename control for owned armies.
• Applies streamed rename responses immediately so the UI does not wait for a bulk resync.
• Falls back to Army plus the short ID when reading pre-change data.

Dependency

The training, battle-summary, and army-name changes require backend PR #24.

Verification

• yarn run check
• yarn build
• targeted ESLint for changed UI/map files
• Prettier check
• git diff --check