G-103: characterize TIP 741 temp-dll cleanup on windows (confirmed flaw)

Ran the copy-to-temp characterization on the suite's own tclsh90szip.exe 9.0.5:
loading a dll out of a zipfs mount extracts it to %TEMP%\TCL<8hex>\<dll>, a new
dir per load, none removed on exit. 'info loaded' reports the //zipfs:/ path so
the temp copy is invisible to script. Unbounded accumulation confirmed in the
wild: 15,609 such dirs in this machine's %TEMP% spanning ~5 months of kit runs.
Windows = the known TIP-741 flaw, no in-runtime cleanup in 9.0.5. Linux/WSL and
qemu guests still to characterize (unix can unlink-while-mapped, so expect no
accumulation - verify).

Assisted-by: harness=claude; primary-model=claude-fable-5; api-location=anthropic.com

goals/G-103-runtime-kit-family.md

@@ -210,3 +210,20 @@ contract the sequencing note promises G-101.
   runtimes are the direct consumers (they load batteries this way). Applies
   equally to G-101's Metakit 8.6 kits (same copy-to-temp).
   Ref: https://core.tcl-lang.org/tips/doc/trunk/tip/741.md
+- 2026-07-21 WINDOWS CHARACTERIZED (suite tclsh90szip.exe 9.0.5): the flaw is
+  REAL and reproduced on the suite's own runtime. Loading a dll out of a zipfs
+  mount ('load //zipfs:/mnt/libbin/tcl9thread307.dll Thread') extracts it to a
+  fresh %TEMP%\TCL<8-hex>\<dll> directory; a NEW directory is created on every
+  such load (observed TCL00011038, TCL0001743c, TCL6185c1b4 across three runs)
+  and NONE is removed on process exit. Notes: (a) 'info loaded' reports the
+  //zipfs:/ path, NOT the temp path - the temp copy is invisible to
+  script-level introspection, only the filesystem reveals it; (b) unbounded
+  accumulation confirmed in the wild - this machine's %TEMP% held 15,609 such
+  TCL* dirs spanning 2026-03-02..2026-07-21 (~5 months), each holding extracted
+  battery dlls from past kit runs (tcl9thread/twapi/tk/tls/sqlite/vfs/tcllibc,
+  incl 8.6-era thread2812/twapi511). So Windows = the known TIP-741 flaw, no
+  in-runtime cleanup in 9.0.5. STILL TO CHARACTERIZE: linux/WSL (G-105) and the
+  G-060 guests - on unix the extracted temp file can be unlink()'d while still
+  mapped, so the expectation there is NO accumulation; verify rather than assume.
+  (Method: mount a zip containing a built dll, load from it, diff %TEMP%/tmpdir
+  before+after and after exit; scratch scripts under the session scratchpad.)