Improve Notification Panel (#3913)

Resolves #3910

## Description:

- Split the events HUD into two components: a new
**`<actionable-events>`** that owns alliance prompts (request / renew)
and a slimmed-down **`<events-display>`** for everything else.
- Reworked `<events-display>` into two visual tiers: dim/scrolling tier
2 on top (trade results, unit losses, donations, alliance status),
prominent tier 1 anchored at the bottom (inbound nukes, naval invasion,
attack requests, alliance broken, conquered player, chat). Tier 2 caps
at the 4 newest entries; events expire after 8s.
- Added a transient **+gold pip** above the gold pill in
`<control-panel>`, animated with a small fade-in. Fires for trade ships,
trains, donations, and conquest. Trade-ship and train arrivals are
removed from the events scroll since they're surfaced here instead.
- New `MessageType.NUKE_DETONATED` and a server-side emission in
`NukeExecution.detonate` — once an inbound nuke lands or gets
intercepted, the inbound warning vanishes and a "detonated" entry takes
its place.
- `displayMessage` gained optional `unitID` and `focusPlayerID` params
so events can link to a unit or a player. Unit captures and destructions
now navigate to the unit's last tile when clicked; donations navigate to
the other player.
- ActionableEvents card width matches `<events-display>`; cards persist
until the user clicks Accept/Reject/Renew/Ignore or the server-side
request timeout expires.
- Removed the in-events category filter UI and the gold-amount banner —
`<events-display>` is now a lightweight log that hides entirely when
empty.

<img width="570" height="444" alt="Screenshot 2026-05-21 at 1 42 30 PM"
src="https://github.com/user-attachments/assets/f103efb3-0e11-4b72-a11b-91ff6896177c"
/>

<img width="430" height="296" alt="Screenshot 2026-05-21 at 1 41 34 PM"
src="https://github.com/user-attachments/assets/ae58475a-b252-4aa6-9ce5-99dea7575ce3"
/>

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

evan

src/client/render/types/GameUpdates.ts

@@ -35,16 +35,6 @@ export const GameUpdateType = {
   NukeDetonation: 22,
 } as const;
 
-/** MessageType enum values from the game source. */
-export const MessageType = {
-  SAM_HIT: 9,
-  SENT_GOLD_TO_PLAYER: 18,
-  RECEIVED_GOLD_FROM_PLAYER: 19,
-  RECEIVED_GOLD_FROM_TRADE: 20,
-  SENT_TROOPS_TO_PLAYER: 21,
-  RECEIVED_TROOPS_FROM_PLAYER: 22,
-} as const;
-
 // ---------------------------------------------------------------------------
 // Typed update payloads (keyed by GameUpdateType values)
 // ---------------------------------------------------------------------------

src/client/render/types/index.ts

@@ -61,7 +61,7 @@ export type {
 } from "./Replay";
 
 // Game update type constants and event payloads (shared between shim + codec)
-export { GameUpdateType, MessageType } from "./GameUpdates";
+export { GameUpdateType } from "./GameUpdates";
 export type {
   AllianceExpiredUpdate,
   AllianceReplyUpdate,