Seamless mouse (VMware backdoor + VBADOS) and fs-backed TOOLS share (#355)

* Seamless mouse via VMware backdoor + fs-backed TOOLS share

v86 (rebuilt libv86.js from fork branch vmware-mouse): new VMwareMouse
device on port 0x5658 implementing GETVERSION/ABSPOINTER_* fed by the
existing mouse-absolute bus event. Move-only packets are coalesced so
the guest cursor never falls more than one frame behind. Emits
vmware-absolute-mouse on the bus when the guest driver toggles mode.

Renderer: listens for that event, keeps the v86 mouse enabled without
pointer lock, drops the startup auto-capture, and hides the host cursor
over the canvas (.seamless-mouse) while the driver is active. Falls back
to click-to-capture when no driver is present.

SMB: TOOLS share is now backed by the bundled guest-tools/ directory
(subdirectories work) with the synthetic README.TXT/_MAPZ.BAT overlaid
at the root. resolve() routes by tid; SEARCH and FIND_FIRST2 share a
single listForSearch helper.

guest-tools/mouse-driver/: VBMOUSE.EXE + VBMOUSE.DRV from VBADOS
(Javier S. Pedro, GPLv2). Load the TSR from AUTOEXEC.BAT and set
mouse.drv=vbmouse.drv in SYSTEM.INI to enable seamless mouse.

Also: tsconfig rootDir "." for TS 6.0 (preserves dist/src/ layout).

* docs: windows95-base now includes vmware-abspointer

.claude/skills/update-v86/SKILL.md

@@ -23,7 +23,7 @@ fallbacks, no fetching from copy.sh.
 ## The fork branch
 
 v86 should be checked out on **`felixrieseberg/v86:windows95-base`**.
-That branch merges two bugfix branches, each with an open upstream PR:
+That branch merges three feature branches, each upstreamable on its own:
 
 - **`electron-renderer-fs-loader`** (PR #1540) — `src/lib.js` uses
   `require("fs")` instead of `await import("node:fs/promises")`. Dynamic
@@ -35,6 +35,11 @@ That branch merges two bugfix branches, each with an open upstream PR:
   writes to target only `current_interface`, but per ATA spec they're
   channel-shared (one register file on the IDE cable; both drives latch
   the same value).
+- **`vmware-abspointer`** — `src/vmware.js` implements the VMware mouse
+  backdoor (port `0x5658`, GETVERSION + ABSPOINTER_*) so a guest driver
+  (VBADOS VBMOUSE) can read absolute cursor position and track the host
+  cursor 1:1 without pointer lock. Consumes the `mouse-absolute` bus
+  event that `MouseAdapter` already emits.
 
 ## Prerequisites