fix(recorder): migrate FiredMan EH to new owner on locality transfer

[fank]

Summary

• Fix shots/hits not being recorded when a player slots into a pre-placed AI unit.
• Refactor the FiredMan/HandleDamage install/remove logic into reusable code values and trigger an install on the new owner whenever the server loses locality.

Root cause

Per BIS wiki, addEventHandler "Local" only fires on machines where it was added. OCAP is server-side only, so the Local EH lives on the server. The previous logic assumed the EH would fire on both old and new owners, but in practice:

1. Mission start: all pre-placed AI are server-local → FiredMan EH installed on server, Local EH installed on server.
2. Player joins and slots into AI: locality transfers server → player.
3. Server's Local EH fires with _isLocal=false → removes its own FiredMan EH.
4. Player's machine never had a Local EH → never installs FiredMan EH.
5. Player fires → no FiredMan EH → no :EVENT:PROJECTILE: ever reaches the extension.

This matched a user report where vehicle kills (server-side EntityKilled) and ACE3 medical events (server-local AI dying) were captured, but zero shots/hits were recorded across a 7-minute session with 10 confirmed kills.

Fix

• Extract the install code into GVAR(ownerInstallBlock) and cleanup into GVAR(ownerRemoveBlock) to eliminate three near-duplicate copies.
• In the server's Local EH _isLocal=false branch, after cleaning up server EHs, remoteExec the install block to owner _entity (which is the new owner at that point).
• Update the misleading "Local EH is global (ironically)" comment to reflect actual semantics.

Delivery pattern is unchanged — install code is still shipped as an inline code block via remoteExec ["call", target], just sourced from a GVAR instead of being inlined three times. No new CfgRemoteExec whitelisting required.

Test plan

• In-game: player slots into a pre-placed AI unit, fires several rounds — verify :EVENT:PROJECTILE: events appear in the extension log at loglevel: debug.
• In-game: fresh player-owned unit (no AI takeover) fires — verify still works (regression check).
• In-game: kill a player, server takes locality back — verify FiredMan EH installs on server (existing path).
• In-game: AI hand-off between server and an HC — verify EH migrates.

[gemini-code-assist]

Code Review

This pull request refactors the event handler management for unit locality changes in fnc_eh_fired_server.sqf, introducing dedicated blocks for installing and removing FiredMan and HandleDamage handlers. This ensures that recording follows the unit's owner, particularly when players take control of AI. A review comment points out that the installation block is not idempotent, which could lead to duplicate event handlers if a unit's ownership changes multiple times, and suggests incorporating a check to remove existing handlers before adding new ones.