test(cli): canonicalize temporary paths on macOS

[en-ver]

Summary

• Canonicalize the CLI test harness TMP_ROOT with physical pwd -P; strict command/CWD/argv assertions stay unchanged.
• No production code, version, or dependency changes.

Root cause

On macOS, /var resolves to /private/var; mktemp -d returns logical /var/folders/..., while a Bun-spawned shell's $PWD reports physical /private/var/folders/.... Raw equality fails despite the same directory and correct command order and arguments.

Solution rationale

Canonicalize the scratch root once before deriving fixtures, aligning the path vocabulary at the test boundary rather than changing production behavior or weakening assertions. This follows existing upstream portability practice.

Validation

• On macOS, the former strict build/CWD assertion passed and the suite progressed to the unrelated final beacon section.
• bun test ./bridge ./cli ./scripts: 3,201 passed.
• scripts/collie-ctl.test.sh: passed.
• Web: 3,844 passed, 18 todo under the Node 26 compatibility option NODE_OPTIONS=--no-experimental-webstorage.
• Lint, root and web typechecks, version gates, and the production build passed.
• The final macOS beacon assertion remains an unrelated Linux /proc limitation; this is not a claim that the complete CLI shell suite is green on macOS.