Yealink: BLF keys from line key 2, named after the extension (or the number, e.g. a parking slot), with **N pickup; keys up to 33 past the last BLF are cleared so removed BLFs leave the phone. Both vendors get the time zone and NTP, and a phonebook URL that carries the phone's credentials (phones fetch it like the config). Time zones: packages/shared/src/phone-timezones.ts maps the US/Canada zones (with aliases), UTC and London to Yealink's offset and name and a POSIX string (Grandstream P64). Anything else is UTC, and the Phones page warns. /prov/phonebook/<mac>.xml (and <mac>/phonebook.xml, the name Grandstream asks for under its path): every extension, then the company contacts that have numbers, in the phone's vendor's format. Same Basic auth as the config. The config preview now masks both secrets wherever they appear (the phonebook URL carries the provisioning password) and says when the time zone falls back. Golden files for both templates and both phonebooks in src/provisioning/__golden__. e2e m10-t2: BLF keys, Central time, the phonebook fetched from the URL in the config, hints for the BLF targets, and the time zone warning. Vendor key names stay (verify per model) until a real phone is checked. Task: M10-T2