feat(sync): show discovery phases and examined item counts

[norgan]

Fixing both lag and visibility of very large file stores

Implementation	Detail
Preparation phases	Starting, discovery and reconciliation
Examined counts	Cumulative classified folders and files; separate from transfer totals
Update frequency	Immediate first count; subsequent count updates at most once per 500 ms; immediate phase transitions
Progress bar	Indeterminate during preparation; no percentage or ETA
Connection state	Disconnected/retry labels
Regression corrections	Known ignored-directory types retained; unknown skipped items excluded from counts; newly opened folder-model rows initialized
Tray updates	Refresh the tray tooltip during starting, discovery and reconciliation; retain the existing transfer and completion behavior
Independent branch	Base 5bf7bdf42c30d93f9896d8fcbe1c44bbc58640af; no batching change from #11086

Local Windows validation	Result
Release client and test build	Passed
DiscoveryProgressTest	12 passed, 0 failed, 0 skipped
RemoteDiscoveryTest	34 passed, 0 failed, 0 skipped
New regression cases against original submitted production code	4 failures reproduced
Tray tooltip regression against the prior published code	11 passed, 1 failed; corrected code: 12 passed, 0 failed
Tray tooltip integration test	Actual Folder progress slot, dispatcher, ownCloudGui and QSystemTrayIcon tooltip exercised with an isolated fake account
Changed-line clang-tidy and clang-format	Passed; no source changes
Isolated model/delegate previews	Discovery, reconciliation, disconnected and retry states inspected
Combined guarded live build	Counts displayed during discovery; Settings/Info navigation responsive
Live tooltip correction	Isolated integration test passed; the existing live scan continues on the earlier protected package
Human review and DCO	Reviewed and signed off
Complete large live sync	Still running; completion unverified
Upstream-before UI screenshot	Unavailable
macOS and Linux validation	Not run in this Windows environment

AI assistance: Assisted-by: Codex:GPT-6 (implementation, tests, source analysis and validation).

[camilasan]

@norgan we will need more information on what you are trying to achieve with this PR.
What exactly you are trying to solve?
You are talking about visibility and you are changing strings, do you have screenshots of the changes?