test(e2e): compare project paths in the Host's stored spelling

[Tioit-Wang]

What

pnpm test:e2e failed on a Windows checkout in two project-removal scenarios, and
the failure was in the assertion's operand rather than in the product.

The Host stores and reports a project path in canonical_project_path spelling:
the directory is resolved and the separators are normalized to /
(crates/host-core/src/db/repositories.rs), so projects.list returns
C:/Users/.../e2e-project-kept on Windows. Both scenarios compared that against
realpathSync, which keeps the platform separators (C:\Users\...), so the
clauses could never be satisfied:

• E2E-PROJECT-delete-removes-project-and-owned-sessions →
  projectsAfter.projects.some((project) => project.path === keptProjectPath)
• E2E-PROJECT-delete-removes-project-and-owned-sessions-refuses-while-running →
  the same comparison inside nothingDeleted

A second clause was disguised by the same mismatch:
projectsAfter.projects.every((project) => project.path !== removedProjectPath)
passed vacuously on Windows, because a backslash spelling can never equal a
slash spelling. Both clauses are about which projects exist, not about separators.

Change

scripts/e2e-smoke.mjs only:

• a storedProjectPath(path) helper — realpathSync(path).replace(/\\/g, "/") —
  reproduces the Host's storage spelling, and the scenarios compare projects.list
  against it;
• the request paths (projects.create, session.create's projectPath,
  project.memory.*, projects.remove) stay platform-native, so the Host is still
  exercised with native input rather than only with a normalized spelling.

Test-only: no renderer, host, IPC, permission, plugin-contract, or schema change,
and no product behavior change, so no spec or E2E scenario document changes.

No issue is closed by this PR; the failure was found while validating the
queue/chat/desktop changes delivered as #429, #430 and #431.

Validation

• pnpm test:e2e on the integrated local main (557bd48b, Windows / PowerShell)
  → exit 0, Summary: 21 / 21 passed; 2 skipped. The 2 skips are
  E2E-008-live-model / E2E-009-stream, which need PI_DESKTOP_TEST_API_KEY.
  Both scenarios that previously failed now report
  PASS E2E-PROJECT-delete-removes-project-and-owned-sessions — removed=true sessionsRemoved=2 artifacts=10->0
  and
  PASS E2E-PROJECT-delete-removes-project-and-owned-sessions-refuses-while-running — refused=1008/CONFLICT then removed=true sessionsRemoved=1.
• Before this change, on 9c72eec0, the same command was exit 1 with
  19 / 21 passed; 2 skipped and byte-identical FAIL lines (the assertion file
  blob 2aa09d54 and the host path code were unchanged between the two runs).
• node --check scripts/e2e-smoke.mjs → clean.

The assertion is stronger after the change, not weaker: the "removed project is
gone" clause can now fail, where before it was a tautology on Windows.