Add grenade trajectory, RPG armour priority, empty chargers, mega gravity gun

- Projectiles gets a "Grenade trajectory" toggle. While a frag grenade is
  held, simulate the weapon_frag throw (1200 u/s forward + 120 z, player
  velocity, gravity 600) and trace each step with a new
  trace_solid_segment(); reflect on impact, stop on a slow upward-normal hit,
  and draw the path, landing cross and a 300-unit blast ring. Verified on :99
  (arcs, bounces off the tunnel wall, lands).
- With the RPG equipped, armoured NPCs (striders, gunships, dropships,
  hunter-choppers) sort before normal enemies during target acquisition.
  Added helicopter/chopper to the ARMORED model list.
- Empty health/suit chargers are hidden: read m_iJuice from the server
  datamap (0 = depleted, -1 = unreadable/fail open).
- The citadel supercharged gravity gun (d3_citadel_03, d3_citadel_04,
  d3_breen_01 via IVEngineClient::GetLevelName) is treated as a normal
  weapon, so the melee aimbot no longer restricts it to VULNERABLE NPCs.

1 files changed, 28 insertions, 7 deletions

diff --git a/CONTEXT.md b/CONTEXT.md
index 1e860bf..889c3ab 100644
--- a/CONTEXT.md
+++ b/CONTEXT.md
@@ -201,9 +201,10 @@ vocabulary / decisions.
 
 - Every NPC is classified for ESP and target selection:
   - `IMMUNE` — server `m_takedamage` is `DAMAGE_NO`/`DAMAGE_EVENTS_ONLY`.
-  - `ARMORED` — gunship, strider, dropship: their `OnTakeDamage` only accepts
-    blast damage (`DMG_BLAST`, with a damage threshold on gunships and a
-    distance check on striders). Only the RPG passes; bullets/grenades do not.
+  - `ARMORED` — gunship, strider, dropship, hunter-chopper: their
+    `OnTakeDamage` only accepts blast damage (`DMG_BLAST`, with a damage
+    threshold on gunships and a distance check on striders). Only the RPG
+    passes; bullets/grenades do not.
   - `VULNERABLE` — headcrab, antlion, manhack: punting them with the gravity
     gun / physics impact damage kills them.
   - `NORMAL` — everything else.
@@ -213,7 +214,10 @@ vocabulary / decisions.
   created at glyph size 10 alongside the 16 px body font (`g_font_small`).
 - Aimbot/silent aim/triggerbot/melee skip `IMMUNE` targets always and
   `ARMORED` targets unless the active weapon is the RPG
-  (`active_weapon_contains` for `rocket_launcher`/`rpg`).
+  (`active_weapon_contains` for `rocket_launcher`/`rpg`). With the RPG
+  equipped, armoured candidates are sorted before normal enemies (a
+  `fov - 1000` rank key), so a strider/gunship is acquired even when a normal
+  NPC is closer to the crosshair.
 - Server `m_takedamage` is a `char` in the 2013 SDK
   (`CNetworkVarForDerived(char, m_takedamage)`, `FIELD_CHARACTER`), so it is
   resolved with that type (int fallback) and read as a byte. `0/1` means no
@@ -402,7 +406,11 @@ vocabulary / decisions.
   `IN_ATTACK`: the primary attack launches a held object along
   `EyeVectors()`. No aim-punch compensation is applied there (EyeVectors does
   not add punch); the crowbar path keeps it. Without a held object the primary
-  is a short physics punch.
+  is a short physics punch. The citadel supercharges the gravity gun
+  (`d3_citadel_03`, `d3_citadel_04`, `d3_breen_01`; detected through
+  `IVEngineClient::GetLevelName`, slot 51), and there it is treated as a
+  normal weapon: the `VULNERABLE`-only filter is dropped, so any damageable
+  hostile NPC is selected.
 - Map transitions often switch the active weapon away from the crowbar. The
   state change is logged as `melee: active ... crowbar=0/1` (normal log), and
   a one-time toast says to equip the crowbar. If the client weapon model is
@@ -694,7 +702,10 @@ vocabulary / decisions.
   Reading at the raw offset shifted every count by one type (e.g. RPG read the
   buckshot count 30 against a max of 3, permanently hiding rockets).
 - Chargers and ammo/supply crates are dispensers and are exempt from the
-  fullness filter.
+  fullness filter. Empty health/suit chargers are still hidden: both
+  `CWallHealth` and `CNewRecharge` expose `m_iJuice` (server datamap
+  `FIELD_INTEGER`, resolved at offset 0x47c in this build), and a value of 0
+  removes the charger tag until it recharges. `-1` (unreadable) fails open.
 - Scans the client entity list every 100 ms and tags health, ammo, armor/suit,
   world weapon pickups, the two supply-crate models and generic items.
 - Each tag is a colored marker with a name and optional distance, filtered by
@@ -733,7 +744,17 @@ vocabulary / decisions.
   is a 24-segment horizontal circle projected at the projectile height, with
   every segment near-plane/screen clipped independently, so it still draws
   when the grenade itself is off-screen or behind the camera.
-  Toggles: Fuse timer, Blast radius.
+  Toggles: Fuse timer, Blast radius, Grenade trajectory
+  (`[projectiles] trajectory=1`).
+- Grenade trajectory: while the frag weapon is active, simulate the throw
+  from `weapon_frag.cpp` (eye + forward*18 + right*8, player velocity +
+  (forward + 0.1 z)*1200), gravity 600, dt 0.02, restitution 0.35, friction
+  0.35. Each step traces with `trace_solid_segment` (EngineTraceClient003 slot
+  4, `MASK_PLAYERSOLID`, local player ignored); hits reflect about the impact
+  normal, and an upward normal with a slow vertical speed marks the landing.
+  The polyline, landing cross and a 300-unit blast-radius ring at the landing
+  are drawn with the same near-plane-clipped projector as the radius ring.
+  Verified on `:99` (the line arcs, bounces off a tunnel wall and lands).
 
 ## Roadmap / TODO