Jumpbug: optional velocity-timed assist

The unduck window is only 2 units, while a 625-ups fall moves ~9.3 units per
66.7 Hz movement command, so pure jumpbug is ~20% reliable at that speed.

- Add Jumpbug -> Assist timing (default off). When the natural next command
  would skip [36,38], pin the post-command ducked distance to 37 by writing
  the vertical velocity for that command. Pure jumpbug remains available with
  the option off.
- Resolve the client local m_vecAbsVelocity (0x11C) via the client datamap
  and the server m_vecAbsVelocity (0x228) via the server datamap.
- Write both the authoritative server velocity (what SetupMove reads through
  GetAbsVelocity) and the local prediction fields, so the next CreateMove sees
  the assisted origin on both sides.
- Do not write the server m_vecVelocity directly: the datamap scan finds two
  same-named entries (0x1C and 0x29C); SetAbsVelocity syncs it after movement.

1 files changed, 17 insertions, 0 deletions

diff --git a/CONTEXT.md b/CONTEXT.md
index b1ec4e7..38d9373 100644
--- a/CONTEXT.md
+++ b/CONTEXT.md
@@ -80,6 +80,7 @@ Relevant vtable slots (this build):
 | `m_vecMins` / `m_vecMaxs` | `0x1A8` / `0x1B4` |
 | `m_lifeState` | `0x7F` |
 | `m_nModelIndex` | `0x7C` |
+| `m_vecAbsVelocity` (client local, not netvar) | `0x11C` |
 
 - 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.)
@@ -106,6 +107,7 @@ HL2hake
     Active
   Jumpbug
     Active
+    Assist timing
   ESP
     Active
     Show neutral / healthbar / healthnum / name / skeleton / box / speed graph
@@ -181,6 +183,21 @@ Binds use SDL scancodes; mouse buttons are pseudo-scancodes 600..604.
 - `drop` is measured from consecutive predicted origins (not a hard-coded tick
   interval). At high fall speeds the 2-unit band can be skipped between
   commands; a higher frame rate improves reliability. Best-effort by design.
+- **Assist timing** (off by default): when the natural next command would jump
+  over the 2-unit window, force the post-command distance to 37 by writing the
+  vertical velocity. It needs both the authoritative server velocity and the
+  client prediction velocity:
+  - server `CBaseEntity::m_vecAbsVelocity` (datamap offset 0x228), read by
+    `SetupMove` via `GetAbsVelocity`;
+  - client `C_BaseEntity::m_vecAbsVelocity` (datamap offset 0x11C) and the
+    networked `m_vecVelocity` (0xE0 + 8).
+  The velocity is `dz / 0.015 + 0.5 * 600 * 0.015` where `dz` is the required
+  displacement for this command. This turns the ~20% timing success at 625 ups
+  into a repeatable setup, at the cost of one command with a nudged vertical
+  speed. Pure jumpbug remains available with Assist off.
+- The server datamap has two `m_vecVelocity` entries (0x1C and 0x29C), so the
+  assist deliberately writes only `m_vecAbsVelocity`; `SetAbsVelocity` syncs
+  `m_vecVelocity` after the command.
 
 ## Gotchas / lessons