#45 Selector health checks + gated debug logging for injected scripts

[Anonymous]

Originally created by: kristofferR

Everything user-facing (badge, notifications, blur, shortcuts) rests on ~71 querySelector/aria-label call sites plus geometry heuristics in `inject/messenger.js`, mostly wrapped in `.catch(() => {})` — when Facebook ships new markup, features die silently.

• Centralize FB DOM selectors into one registry with per-feature "did this match anything?" health counters.
• Add a gated `CARRIER_DEBUG` logger (off by default).
• Surface a one-time toast when a core selector stays dry for N minutes ("a Messenger update may have broken X — check for updates").

This creates the fix-fast loop: a user report maps directly to the selector that died.

[Anonymous]

Originally posted by: kristofferR

Done in [#62]: selector-health watch over the core selectors with a one-time user-facing toast, plus the rate-limited diag() reporter feeding the native log. Full migration of every selector call site to the registry rides with the inject toolchain (#48).

[Anonymous]

Ticket changed by: kristofferR

• status: open --> closed