Docs/cleanup: refresh CONTEXT, update ISurface status, remove dead code

- rewrite CONTEXT.md for the current architecture, interfaces, netvars,
  menu tree, bones/ESP, aimbot/vischeck, triggerbot, silent aim and ABH
- update ISURFACE_STATUS.md: DrawLine slot, current menu/config path,
  9 build TUs, current file layout
- remove the stale root-level `tree` file
- drop unused class_health_off/per-class health scan (NPC HP is not
  networked), surf_call_slot, and unused scancode helpers

1 files changed, 153 insertions, 32 deletions

diff --git a/CONTEXT.md b/CONTEXT.md
index 21128f7..1969781 100644
--- a/CONTEXT.md
+++ b/CONTEXT.md
@@ -1,47 +1,168 @@
 # Context: HL2 Linux Internal Cheat (`hl2hake`)
 
-## What is this project?
+## What this is
 
-A minimal, featureless cheat for Half-Life 2 (native Linux build, 32-bit `hl2_linux`). Originally ported from a Windows reference (`hake`) that implemented auto-bhop, auto-ABH, and auto-climb via a `CHLClient::CreateMove` vtable hook.
+A 32-bit Linux internal for Half-Life 2 (native `hl2_linux`), loaded with
+`LD_PRELOAD` through Steam's bundled 32-bit runtime. It started as a port of
+the Windows `hake` reference (auto-bhop / auto-ABH / auto-climb) and now also
+covers ESP, aimbot, triggerbot and silent aim.
 
-## Resolved terms
+## Build / run
 
-- **Build**: LD_PRELOAD a 32-bit `.so` into `hl2_linux` via Steam's bundled 32-bit runtime (`steam-runtime/run.sh`).
-- **Hook**: Copy-and-swap vtable on the `CHLClient` instance (slot 21 = `CreateMove`). 256-slot copy to cover all dispatched virtuals.
-- **Netvars**: RecvTable walk from `IBaseClientDLL::GetAllClasses` (vtable slot 8). Prediction datamap scan for `CBaseEntity::m_MoveType` (networked `movetype` is a virtual proxy with offset 0).
-- **CInput**: Discovered via byte-scan of `CHLClient::CreateMove` prologue (gcc PIC `call thunk; add $imm,%esi` idiom), resolving the module-level `IInput*` variable.
-- **UserCMD CRC**: Standard CRC-32 (IEEE reflected, poly `0xEDB88320`, init `0xFFFFFFFF`). Field set and offsets verified against the binary's `CInput::ValidateUserCmd` disassembly.
-- **Module discovery**: `/proc/self/maps` scan for `client.so` / `engine.so` basenames (exact match at `/` boundary). PROT_NONE (`---p`) entries excluded. Merged file-backed ranges absorb one directly-adjacent anonymous `.bss` tail; anon-to-anon chaining is prohibited.
-- **Calling convention**: All game virtuals use **cdecl** with `this` as first stack arg (`0x8(%ebp)` in prologues, bare `ret`). No MSVC `__thiscall`.
+- `./build.sh` -> `libhl2hake.so`
+  (`g++ -m32 -O2 -std=c++17 -Wall -Wextra -Werror -fPIC -shared`,
+  sources: `hl2h modules cinput netvars menu esp server bones vischeck`, `-ldl`).
+- `./play.sh` -> Steam runtime + `hl2.sh -steam -novid -console +map d1_town_01`.
+- Logs: `/tmp/hl2hake.log` (`logf`) and stderr. `./play.sh > /tmp/hl2run.log 2>&1`
+  captures everything.
+- Debug env:
+  - `HL2H_DRAW_TEST=1` — red probe rect + text, no menu needed.
+  - `HL2H_BONE_DEBUG=1` — white marker at each NPC head hitbox.
+  - `HL2H_NO_SERVER=1` — disable server-side health reads.
+- Config: `$XDG_CONFIG_HOME/hl2hake/config`, falling back to
+  `~/.config/hl2hake/config`. Plain INI, saved on every change.
 
-## Netvar offsets (this build, verified via both RecvTable walk and pred-TD scan)
+## Runtime architecture
 
-| Field | Offset | Source |
-|---|---|---|
-| `m_fFlags` | `0x33C` | RecvTable + pred TD |
-| `m_vecVelocity[0]` | `0xE0` | RecvTable (array, FIELD_VECTOR) |
-| `m_MoveType` | `0x164` | pred-TD only (networked `movetype` has offset 0) |
+- Modules from `/proc/self/maps`: `client.so`, `engine.so`, `server.so`.
+  PROT_NONE ranges excluded; file-backed bss tails merged.
+- Calling convention: cdecl (i386); `this` is the first stack argument.
+- Hooks (copy-and-swap vtable, 256 slots):
+  - `CHLClient` slot 21 `CreateMove`; slot 35 `FrameStageNotify`.
+  - `ISurface` slot 114 `PaintTraverseEx` (primary draw);
+    slot 22 `DrawPrintText` fallback. Draws wrapped in
+    `PushMakeCurrent`/`PopMakeCurrent`.
+- `CInput*` discovered by byte-scanning the `CHLClient::CreateMove` prologue.
+  Usercmd CRC-32 is repaired after any cmd edit (`note_modified`).
+- Console output via `ConMsg` from `libtier0.so`
+  (`_Z6ConMsgPKcz`), not `IVEngineClient::ClientCmd`.
 
-## Key engine index table (IVEngineClient014, this build)
+## Interfaces / indices
 
-| Index | Method | Verification |
+| Interface | Version | Notes |
 |---|---|---|
-| 8 | *(not ClientCmd)* | Disasm: per-player index bounds check on `(arg-1)` — likely `GetPlayerInfo` |
-| 9 | *(not ClientCmd_Unrestricted)* | Disasm: loop over split-screen players — no-op'd in single-player |
-| 12 | `GetLocalPlayer` | Disasm: `return *(CClientState + 0x1b0) + 1` — confirmed in-game |
-| 65 | `HudUpdate`-family | Crash-site (256-slot bump): `call *(this, float)` |
+| Client | `VClient017` | |
+| Entity list | `VClientEntityList003` | |
+| Engine | `VEngineClient014` | |
+| Model info | `VModelInfoClient006` | |
+| Engine server | `VEngineServer021` | edicts / listen-server entities |
+| Debug overlay | `VDebugOverlay003` | accurate world->screen |
+| Engine trace | `EngineTraceClient003` | vischeck / trigger ray |
+| Surface | `VGUI_Surface030` | |
+
+Relevant vtable slots (this build):
+
+- Engine: `GetLocalPlayer` 12, `Time` 14, `GetViewAngles` 19, `SetViewAngles` 20.
+- Entity list: `GetClientNetworkable` 0, `GetClientEntity` 3,
+  `GetHighestEntityIndex` 6.
+- `IClientNetworkable`: `GetClientClass` 2. `ClientClass::m_pNetworkName` at +8.
+- `IClientUnknown`: `GetClientRenderable` 6.
+- `IClientRenderable`: `GetModel` 9, `SetupBones` 16.
+- `IVModelInfo`: `GetModel` 2, `GetModelName` 4, `GetStudiomodel` 29.
+- `IVEngineServer`: `PEntityOfEntIndex` 19.
+  Edict `m_pUnk` at +0xC; `IServerUnknown::GetBaseEntity` 6.
+- `IVDebugOverlay`: `ScreenPosition` 9.
+- `IEngineTrace`: `TraceRay` 4. `Ray_t` uses 16-byte `VectorAligned`;
+  `trace_t`: `fraction` 44, `startsolid` 55, `m_pEnt` 76.
+
+## Netvars / entity data (this build)
+
+| Field | Client offset |
+|---|---|
+| `m_fFlags` | `0x33C` |
+| `m_vecVelocity[0]` | `0xE0` |
+| `m_MoveType` (prediction datamap) | `0x164` |
+| `m_iHealth` | `0x80` |
+| `m_iMaxHealth` | not networked |
+| `m_iTeamNum` | `0x88` |
+| `m_vecOrigin` | `0x324` |
+| `m_vecViewOffset[0]` | `0xD4` |
+| `m_vecMins` / `m_vecMaxs` | `0x1A8` / `0x1B4` |
+| `m_lifeState` | `0x7F` |
+| `m_nModelIndex` | `0x7C` |
+
+- Eye position = `m_vecOrigin + m_vecViewOffset` on **all three axes**.
+  (The old code added the X component to Z, which left the eye ~64 units low.)
+- NPC health is not networked. Alive state comes from the networked client
+  `m_lifeState`; real HP is read from the listen-server `CBaseEntity` found via
+  `PEntityOfEntIndex -> edict->m_pUnk -> GetBaseEntity`, using offsets scanned
+  from `server.so`'s datamap:
+  - `m_iHealth` `0xF4`, `m_iMaxHealth` `0xF0`,
+    `m_lifeState` `0xF8`, `m_nModelIndex` `0x7A` (short).
+
+## Menu
+
+Starts fully collapsed on first open. `Insert` toggles; `Up`/`Down` navigate;
+`Enter` expands/toggles; `Left`/`Right` edit values; `Escape` closes.
+Bind rows enter bind-select mode: press a key/button to assign, `Escape` sets
+None (always-on), `Enter` cancels.
+
+```
+HL2hake
+  Bunnyhop
+    Active
+    Uni-directional auto-strafe
+  ABH
+    Active
+  ESP
+    Active
+    Show neutral / healthbar / healthnum / name / skeleton / box
+  Aimbot
+    Active
+    Bind
+    Vischeck
+    Bones -> Head / Torso / Left arm / Right arm / Left leg / Right leg
+    Smoothness (1..45 deg/tick, Left/Right)
+  Triggerbot
+    Active
+    Bind
+  Silent aim
+    Active
+    Bind
+```
+
+Binds use SDL scancodes; mouse buttons are pseudo-scancodes 600..604.
+
+## Bones / ESP
 
-Console output uses `ConMsg` from `libtier0.so` (resolved via `dlsym(RTLD_DEFAULT, "_Z6ConMsgPKcz")`), not `IVEngineClient::ClientCmd`.
+- `SetupBones(BONE_USED_BY_ANYTHING)` with engine `Time()`; studio header via
+  `GetStudiomodel`; hitboxes and bone names/parents from that header.
+- HL2 strips many ValveBiped bone names (the zombie's spine/legs/left arm are
+  unnamed), so the humanoid skeleton is built from the **union of hitbox bone
+  parent paths** (`HITGROUP_*`). Head group 1 includes the zombie headcrab body
+  and its `HC_Head` child; fingers, toes and other `HC_*` limbs are excluded.
+- Non-humanoid NPCs (headcrabs, crows, antlions, ...) draw the full bone tree.
+- `aim_points` = head hitbox/bone + hitbox centers for the selected groups;
+  the aim features pick the nearest visible point.
 
-## Menu system
+## Aim features
 
-- **Toggle architecture**: each feature is runtime-toggleable, ON by default. A `MenuState` struct holds per-feature `active` bool and `bind` (key code or None).
-- **Rendering**: hook `IEngineVGui::Paint` via `VEngineVGui001` — draws every frame including the main menu. Text-only overlay in top-left corner.
-- **Persistence**: INI-style plain text config; one line per setting (`climb_active=1`, `climb_bind=MOUSE3`). Config written on every state change; loaded before hooks install.
-- **Input model**: Insert toggles menu open/closed; arrow keys navigate the tree; Enter expands/collapses nodes and toggles boolean fields; Escape closes the menu. Modal while open (all game input blocked). Long-term: selective pass-through for unused inputs.
-- **Bind assignment UX**: selecting a Bind node enters bind-select mode; any key press becomes the new bind; Escape sets bind to None (disabling the feature); Enter cancels bind change and reverts.
-- **Tree layout**: HL2hake (root) → Climb (Active + Bind), Bunnyhop (Active), ABH (Active). Children indented. All nodes expanded by default when the menu opens.
+- Shared target selection (`select_aim_target`): live hostile NPCs, skip
+  friendly/neutral, rank by angle to the crosshair, then pick the nearest
+  selected hitgroup point. Target candidates are tried nearest-first.
+- Vischeck: `EngineTraceClient003::TraceRay`, `MASK_VISIBLE`,
+  `TRACE_WORLD_ONLY` (world only; static props are not tested — deliberate).
+- Aimbot: bounded smoothing — 0.05 deg deadzone, max `Smoothness` deg/tick,
+  shortest-path yaw, pitch clamped to ±89; pushes the new view with
+  `SetViewAngles`.
+- Triggerbot: crosshair ray with `MASK_SHOT` + `TRACE_EVERYTHING` (filter
+  ignores the local player). First hit must be a live hostile NPC; sets
+  `IN_ATTACK`.
+- Silent aim: exact target angle written to `cmd->viewangles`, `IN_ATTACK`,
+  then the rendered view is restored immediately **and** at
+  `FRAME_RENDER_START`; `forwardmove`/`sidemove` are rewritten to preserve the
+  world-space movement wish vector.
+- ABH: on the landing/jump tick, face opposite the horizontal velocity with
+  zero forward/side movement; HL2's jump speed-bound subtraction then
+  accelerates along the velocity. Camera restored at `FRAME_RENDER_START`.
 
-## Open questions
+## Gotchas / lessons
 
-None currently.
+- Never pipe-mask build failures:
+  `./build.sh > /tmp/build.log 2>&1; echo rc=$?`.
+- `CHLClient` slot numbers: `CreateMove` 21, `FrameStageNotify` 35.
+- `ISurface` binary slot = SDK header slot + 4; see `src/ISURFACE_STATUS.md`.
+- Silent aim and ABH temporarily replace the usercmd view; silent aim preserves
+  movement, ABH intentionally zeroes it for the jump tick.
+- Aimbot vischeck (`MASK_VISIBLE`/world-only) differs from triggerbot
+  (`MASK_SHOT`/all entities): glass and static props can behave differently.