Filter un-cleanable items at module boundary, not just ScanCoordinator (1.5.2)

[iliyami]

Why this is needed (the 1.5.1 fix was incomplete)

Real-world test on 1.5.2 produced the exact same 10 errors 1.5.1 was supposed to eliminate. Root cause: the 1.5.1 filter sat in ScanCoordinator.scanModules, which is only the Smart Scan path. The per-module Clean flows — the ones users actually hit when they open System Junk, Mail Attachments, Trash Bins, Malware, Privacy, Large & Old Files, or Duplicates — all bypass the coordinator and call module.scan() directly from their views/view models. Those direct callers got unfiltered results.

SystemJunkViewModel.swift:57   async let scanTask = module.scan()
MailAttachmentsView.swift:53   async let scanTask = module.scan()
MalwareView.swift:53           async let scanTask = module.scan()
LargeOldFilesView.swift:52     async let scanTask = module.scan()
TrashBinsView.swift:54         async let scanTask = module.scan()
PrivacyView.swift:53           async let scanTask = module.scan()
DuplicatesView.swift:167       let scanResults = await module.scan()

System Junk is the primary feature, and its viewmodel was the one the user's repro hit.

The fix

Push the filter into the module, so the contract travels with the result:

A ScanModule.scan() only returns items the current process could trash.

Mechanically: Array<ScanResult>.filteringUncleanable() is added in MacCleanKit/CleanFilter.swift, and every producing module's scan() calls it before returning. ScanCoordinator's inline filter is left in place as belt-and-suspenders — modules now do the work, but a forgetting-prone future module still gets caught for Smart Scan.

Files touched

• Sources/MacCleanKit/CleanFilter.swift — new Array<ScanResult>.filteringUncleanable() extension.
• 7 producing modules — append .filteringUncleanable() to their scan() return:
  • SystemJunkModule, MailAttachmentsModule, TrashBinsModule, MalwareModule, PrivacyModule, DuplicatesModule, LargeOldFilesModule
• 6 non-producing modules untouched (Optimization, Maintenance, Updater, Uninstaller, SpaceLens, Shredder all return [] from scan() and use sidecar managers).
• Tests/MacCleanKitTests/CleanFilterTests.swift — one new test asserting the array extension preserves category and autoSelect while dropping un-cleanable items.
• VERSION + MCConstants.appVersion → 1.5.2.

Test plan

• swift test — 388 tests, 4 skipped, 0 failures
• swift build — clean
• Version sync OK
• Local install of the 1.5.2 DMG: System Junk clean shows 0 errors (or only real ones, not the prior 10 fixtures)
• CI green, Release green, brew cask synced after merge