fix: match WSL session list cwd casing

[kocaemre]

Summary

• normalize /mnt/<drive>/... cwd filters before calling the Claude SDK session index
• keep non-WSL paths case-preserving
• add session/list coverage for the WSL drive-path case

Fixes #1041

Verification

• npm run test:run -- src/tests/acp-agent.test.ts -t 'session/list'
• npm run test:run -- src/tests/acp-agent.test.ts
• npm run build
• npm run check
• git diff --check

I also ran npm run test:run; it reached 1044 passed, 27 skipped and failed only the two existing root-environment resolvePermissionMode expectations where bypassPermissions is downgraded to default when tests run as root.

[kocaemre]

Rebased this PR onto current main after the branch became conflicting (DIRTY). The only conflict was in src/tests/acp-agent.test.ts; I kept the newer upstream importSessionToStore fork-session test setup and the PR's listSessions mock/session-list tests together.

Validation on the refreshed branch:

• npm ci — passed (248 packages installed, 0 vulnerabilities)
• npm run test:run -- src/tests/acp-agent.test.ts -t 'session/list' — passed (2 passed, 493 skipped)
• npm run build — passed (tsc)
• npm run check — passed (eslint + prettier --check)
• git diff --check origin/main..HEAD — passed

I also ran the full npm run test:run; it reached 1230 passing / 27 skipped, but failed 6 tests outside this PR's touched behavior: three timeouts in existing suites, the two known root-environment resolvePermissionMode expectations, and one hook timeout in session-config-options. The targeted session/list, build, lint, and format checks above are green after the rebase.

[kocaemre]

Rebased this PR onto current main (d870ebd2) after upstream moved and force-pushed refreshed head 9fa0b1f.

No code changes beyond replaying the existing WSL cwd normalization commit on top of the current branch.

Local verification in this cron environment:

git diff --check origin/main..HEAD
# passed

npm run test:run -- src/tests/acp-agent.test.ts -t 'WSL|session list cwd casing|non-WSL cwd filters'
# passed: 2 tests, 493 skipped

npm run check
# passed: eslint src --ext .ts + prettier --check .

npm run build
# passed: tsc

I also tried the broader file-level suite:

npm run test:run -- src/tests/acp-agent.test.ts

It ran 495 tests and passed 485 with 9 skipped, but timed out in the pre-existing broad-suite test stop reason propagation > forwards background output that arrives after the turn resolves (issue #679). The focused WSL regression tests for this PR passed after the rebase.

DCO sign-off is preserved on the PR commit.