fix(controller): platform-aware process table, kill fallbacks, and install-job cancellation

[luminary19]

Summary

Process discovery ran ps, kill fallbacks ran sudo -n kill, and install
cancel signalled only the direct child — all no-ops or leaks on Windows. The
process inventory now goes through a platform seam: Get-CimInstance Win32_Process (UTF-8, JSON) on win32, the existing ps path elsewhere, with
command lines tokenized by the shared quote-aware splitter instead of split on
spaces. Kill fallbacks use taskkill /PID <pid> /T /F on win32 and skip the
meaningless sudo attempt; install-job cancellation kills the child tree; the
running-process python probe reads the command line via CIM on Windows. POSIX
paths are unchanged. Fixes #210.

Validation

bun run typecheck and bun run lint clean; the new
parseWindowsProcessInventory unit test passes. Verified live on Windows 11
that listProcessInventory() returns the real CIM process table (377 processes,
correct pid/ppid, quoted command paths tokenized). The POSIX branch is
byte-identical to the previous listProcessInventory (Linux takes the unchanged
ps path), so CI is unaffected.

Note: the existing process-manager-spawn integration suite has Windows-only
fixture issues (extensionless fake binaries, a POSIX-shaped orphan-sweep
expectation) that are addressed by the separate test-portability PR; on Linux CI
that suite runs the unchanged POSIX path and passes.

UI changes

None.

Risks / rollout notes

• CIM via PowerShell adds ~100-300ms per cold snapshot on win32 only; the
  snapshot is cached for the poll tick to avoid repeated forks.
• taskkill /F is a hard kill — used only where SIGKILL was already the
  intent.