Fix deterministic workspace indexing and search

[jkaunert]

Description

This PR makes workspace search indexing and search result publication deterministic.

It keeps the existing addProjectToIndex() startup behavior as fire-and-forget, but moves the actual indexing work into an awaitable indexProject() path. That lets tests and explicit re-indexing callers wait until the index has been flushed instead of polling indexStatus with timing loops.

The patch also replaces the search path's DispatchGroup plus nested Task completion handling with structured concurrency. search(_:) now awaits result evaluation before publishing final search results, so callers do not observe stale or partially populated state.

This is intentionally narrower than #1993. It does not replace the task notification system or introduce the broader activity manager refactor. The goal is to land the lifecycle contract fix first so indexing/search behavior is stable before any notification or activity API cleanup continues.

Main changes:

• Add cancellable indexing task ownership to WorkspaceDocument.SearchState
• Keep addProjectToIndex() non-blocking for startup
• Add indexProject() async for deterministic indexing and tests
• Publish indexing progress from main-actor helpers
• Make search(_:) await result evaluation before setSearchResults()
• Remove timing-based polling from workspace search/index tests

Related Issues

• Refs Refactored Activities for clarity and a consistent API #1993

Checklist

• I read and understood the contributing guide as well as the code of conduct
• The issues this PR addresses are related to each other
• My changes generate no new warnings
• My code builds and runs on my machine
• My changes are all related to the related issue above
• I documented my code

Validation

Ran with XcodeBuildMCP on macOS using -skipPackagePluginValidation.

• Focused tests: 22/22 passed
  • CodeEditTests/TaskNotificationHandlerTests
  • CodeEditTests/WorkspaceDocumentIndexTests
  • CodeEditTests/FindTests
  • CodeEditTests/FindAndReplaceTests
• Full CodeEditTests: 140 passed, 0 failed, 2 skipped
• git diff --check: clean

Note: the test run still reports an existing trailing-whitespace warning in CodeEdit/WorkspaceView.swift:90, which is outside this diff.

Screenshots

Not applicable. This PR changes workspace indexing/search lifecycle behavior and tests, not UI presentation.

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

This PR refactors workspace search indexing to use structured concurrency with cancellable tasks, and updates tests to use the new async indexing API.

Changes:

• Introduced a cancellable indexingTask and new async indexProject() API, while keeping addProjectToIndex() as a non-blocking entry point.
• Reworked indexing progress publishing into MainActor-isolated helper methods and added cancellation cleanup.
• Simplified tests by awaiting indexing completion instead of polling with timeouts.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
CodeEdit/Features/Documents/WorkspaceDocument/WorkspaceDocument+SearchState.swift	Adds indexingTask lifecycle management and cancels indexing on deinit.
CodeEdit/Features/Documents/WorkspaceDocument/WorkspaceDocument+Index.swift	Refactors indexing into cancellable async flows; adds indexProject() and progress publishers.
CodeEdit/Features/Documents/WorkspaceDocument/WorkspaceDocument+Find.swift	Switches result reset/search evaluation to structured concurrency and MainActor-safe updates.
CodeEditTests/Features/Documents/WorkspaceDocument+SearchState+IndexTests.swift	Updates tests to await indexProject() and assert completion state.
CodeEditTests/Features/Documents/WorkspaceDocument+SearchState+FindTests.swift	Updates tests to await indexProject() and assert completion state.
CodeEditTests/Features/Documents/WorkspaceDocument+SearchState+FindAndReplaceTests.swift	Updates tests to await indexProject() and removes polling waits.

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[jkaunert]

@thecoolwinter sorry for the direct ping, but you look like the most active recent maintainer in the repo history. Could you approve the fork PR workflow or route this to the right reviewer when you have a chance?

Copilot review comments have been addressed and resolved in 9f20f532.

Local validation after the update:

• Focused search/index/notification slice: 22 passed, 0 failed
• Full CodeEditTests: 140 passed, 0 failed, 2 skipped
• git diff --check: clean

The GitHub Actions run is currently action_required with no jobs started, so it looks like CI is waiting for maintainer approval rather than failing on the branch.