v2026.08.05

This release completes the account-pool cleanup and tightens the registration,
mailbox, proxy, and desktop boundaries.

Account pool

Removed 10 terminal rows classified as dropped/deactivated or missing/invalid
AT. The active SQLite pool now contains 419 rows with no missing AT records.
Unknown network/proxy results were retained for recheck instead of being
treated as account failures.
Added sms_tool.account_cleanup and the dry-run-by-default
scripts/cleanup_invalid_accounts.py. Applying cleanup creates a database
backup and archives matching session files before removing mailbox-pool lines.

Registration proxy resolution now uses only registration/default settings and
distributes healthy static proxies across workers and retries.
Mailbox selection accepts iCloud receive URLs through the mixed compatibility
route; iCloud listing and message-detail fetching are separate operations and
OTP polling ignores the initial snapshot.
Proxy credentials are normalized at transport boundaries and redacted from
liveness, Sentinel, and registration errors.
WPF selected-mailbox and failed-account reruns share one format-aware mailbox
file builder, keeping provider parsing out of window handlers.

Removed generated Python/.NET test caches and intermediate build output; local
config.json, sessions/, and runtime/ remain ignored operator state.
Verified pytest -q (620 passed, 1 skipped, 22 subtests) and Python bytecode
compilation. The .NET SDK selector now accepts the installed 10.0.302 feature
band while CI remains pinned by global.json compatibility rules.