Fix critical bugs: off-by-one crash, OCR data race, DB recovery, accessibility prompt

[twitchyvr]

Summary

Five targeted fixes for bugs found during code review — no new features, no model changes, no behavioral shifts.

1. Off-by-one crash in AppIntents (Get, Select, Delete)

Files: Intents/Get.swift, Intents/Select.swift, Intents/Delete.swift

The bounds check items.count >= index allows items[items.count], which is out of bounds. For example, with 5 items, requesting item #5 yields index = 4, and 5 >= 4 passes the guard, but items[4] is valid — however, requesting item #6 yields index = 5, and 5 >= 5 passes the guard, then items[5] crashes. More critically, when items.count == index (boundary case), the access crashes.

Fix: Changed to index >= 0 && index < items.count — standard bounds checking that also prevents negative index access.

2. Data race in Vision OCR callback

File: Models/HistoryItem.swift

recognizeTextHandler runs on an arbitrary Vision framework queue and writes directly to self.title. Since HistoryItem is a @Model class, its properties should only be mutated on the main actor (the model context's actor). This is a data race that can corrupt SwiftData's change tracking.

Fix: Dispatch the title update to DispatchQueue.main.async.

3. Graceful database recovery instead of fatalError

File: Storage.swift

If ModelContainer creation fails (corrupt SQLite from forced quit, disk error, etc.), the app calls fatalError() and is permanently bricked until the user manually deletes ~/Library/Application Support/Maccy/Storage.sqlite.

Fix: Catch the error, delete the corrupt .sqlite, .shm, and .wal files, and retry container creation. The user loses history but the app remains functional. Only fatalErrors if re-creation also fails.

4. Cache compiled regexes in clipboard ignore check

File: Clipboard.swift

shouldIgnore(_ item:) creates new NSRegularExpression objects for every pattern on every clipboard poll (default: every 0.5s). Regex compilation is expensive.

Fix: Cache compiled regexes and only recompile when the user's pattern list changes. Also restructured to extract the string once before the loop.

5. Prompt user for accessibility permissions

Files: Accessibility.swift, Clipboard.swift

Accessibility.check() was a no-op when permissions were missing — it returned silently, and paste() would proceed to simulate keyboard events that did nothing. Users had no indication why paste wasn't working.

Fix: check() now returns a Bool and triggers the macOS accessibility permissions prompt via AXIsProcessTrustedWithOptions with the prompt option. paste() gates on the return value.

Test plan

• Verify AppIntents work via Shortcuts app with boundary item numbers
• Copy an image to trigger OCR — confirm no crash or unexpected behavior
• Simulate corrupt database (rename Storage.sqlite to corrupt it) — verify app recovers
• Add ignore regex patterns — verify clipboard polling remains performant
• Revoke accessibility permissions — verify paste prompts for permissions instead of silently failing
• General regression: copy, paste, search, pin/unpin, delete all work as before

🤖 Generated with Claude Code

[twitchyvr]

CI Note

The Bitrise CI run shows testCopyRTF failing (all 3 retries) — this is not related to this PR.

The failure is an RTF title parsing issue on the CI VM:

XCTAssertEqual failed: ("["foo", "DC74B875-..."]") is not equal to ("["foo", "bar"]")

The RTF NSAttributedString parser returns a UUID instead of the parsed text "bar" — likely a font/text services issue on the CI's macOS Sequoia VM. The test suite reports 38 tests, 6 failures (0 unexpected), confirming these are known/expected failures.

This PR does not modify:

• Any test files (git diff upstream/master..fix/critical-bugs-and-performance -- MaccyUITests/ is empty)
• generateTitle() or previewableText (the RTF parsing path)
• Any RTF handling code

The only HistoryItem.swift change is dispatching the Vision OCR callback to the main queue — completely unrelated to RTF.