[follow-up] Preserve current health across relog like C++

[alseif0x]

Follow-up from #79 live validation. #79 fixed current power/mana persistence; current health has the same C++ save/load shape but should be handled as its own focused issue.

Context

C++ saves current health and current powers to characters, then on load recalculates stats/max values and restores saved current health/powers clamped to their new maximums. Rust now handles represented current power correctly for #79, but current health still appears to be initialized from max health during login/stat setup and is not clearly persisted from the canonical/session player state on save.

C++ anchors

• Player::SaveToDB writes GetHealth() before the class power fields: /home/server/woltk-trinity-legacy/src/server/game/Entities/Player/Player.cpp
• Player::LoadFromDB reads fields.health, marks zero health as corpse/dead state, runs stat recalculation, then restores SetHealth(min(savedHealth, GetMaxHealth())): /home/server/woltk-trinity-legacy/src/server/game/Entities/Player/Player.cpp
• The same load block restores fields.powers[] into current powers clamped to max; use this as the sibling behavior, not as a substitute for health.

Current Rust gap

• Login/stat setup has paths that construct player combat stats with health: max_health.
• The [02.1 follow-up] Fix SpellPower review issues from PR #78 #79 save snapshot tracks current powers, but current health is not clearly part of the C++-like snapshot/update path.
• This means a damaged but alive character can plausibly relog as full health, which is not C++ parity.

Do

• Load characters.health as the saved current health field and keep it distinct from power1 and max-health calculations.
• After base stats/items/auras recalculate max health, restore current health as min(saved_health, max_health) like C++.
• Preserve the C++ zero-health/death-state behavior boundary; do not paper over death/corpse flows by forcing max health.
• Save current health from the authoritative canonical/session player state on logout/disconnect/periodic save where Rust already saves represented current powers.
• Do not implement offline health regeneration here; offline rest belongs to [follow-up] Rested XP + offline rest-state parity #81 and should not refill resources.

Tests

Add focused positive/negative tests for:

• damaged alive player relogs with the same current health, not max health.
• saved health above recalculated max clamps to max.
• zero saved health keeps the C++ death/corpse boundary intact.
• health persistence does not overwrite or shift power1..power10 fields.
• logout/disconnect save snapshot includes current health from the authoritative runtime player.

Related

• [02.1 follow-up] Fix SpellPower review issues from PR #78 #79 fixed current power persistence after spell casts/relog.
• [follow-up] Rested XP + offline rest-state parity #81 tracks rested XP/offline rest-state parity and explicitly should not refill health/power.
• [54] [M5.5] Instance enter/leave basics + reconnect/logout integrity #45 tracks broader reconnect/logout integrity.
• [51] [M5.2] Resurrection / corpse / graveyard #43/[50] [M5.1] Death -> ghost: PLAYER_FLAGS_GHOST, durability loss, restrictions #42 may cover death/corpse/graveyard behavior that intersects the zero-health boundary.

Done means C++-anchored implementation, focused tests, PROTOC=/home/cdmonio/.local/protoc/bin/protoc cargo check/test, and live validation of damaged-player relog behavior against the running server.