provisioning: BLF keys, time zone table, company phonebook

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

packages/shared/src/index.ts

@@ -18,6 +18,7 @@ export * from './queues.ts';
 export * from './conferences.ts';
 export * from './paging.ts';
 export * from './devices.ts';
+export * from './phone-timezones.ts';
 export * from './ivrs.ts';
 export * from './timeconditions.ts';
 export * from './announcements.ts';

packages/shared/src/phone-timezones.ts

@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: AGPL-3.0-or-later
+// Company time zone → what desk phones want (07 §3.4): Yealink's offset and zone name, and a POSIX
+// TZ string (Grandstream). Yealink names and the Grandstream format are (verify per model).
+// Anything not listed falls back to UTC, and the Phones page says so.
+export type PhoneTimezone = { yealinkOffset: string; yealinkName: string; posix: string };
+
+const US_DST = 'M3.2.0,M11.1.0';
+const EASTERN = {
+  yealinkOffset: '-5',
+  yealinkName: 'United States-Eastern Time',
+  posix: `EST5EDT,${US_DST}`,
+};
+const CENTRAL = {
+  yealinkOffset: '-6',
+  yealinkName: 'United States-Central Time',
+  posix: `CST6CDT,${US_DST}`,
+};
+const MOUNTAIN = {
+  yealinkOffset: '-7',
+  yealinkName: 'United States-Mountain Time',
+  posix: `MST7MDT,${US_DST}`,
+};
+const PACIFIC = {
+  yealinkOffset: '-8',
+  yealinkName: 'United States-Pacific Time',
+  posix: `PST8PDT,${US_DST}`,
+};
+export const UTC_PHONE_TZ: PhoneTimezone = {
+  yealinkOffset: '0',
+  yealinkName: 'UTC',
+  posix: 'UTC0',
+};
+
+export const PHONE_TIMEZONES: Record<string, PhoneTimezone> = {
+  'America/New_York': EASTERN,
+  'America/Detroit': EASTERN,
+  'America/Toronto': EASTERN,
+  'America/Chicago': CENTRAL,
+  'America/Winnipeg': CENTRAL,
+  'America/Denver': MOUNTAIN,
+  'America/Edmonton': MOUNTAIN,
+  'America/Boise': MOUNTAIN,
+  'America/Phoenix': {
+    yealinkOffset: '-7',
+    yealinkName: 'United States-MST no DST',
+    posix: 'MST7',
+  },
+  'America/Los_Angeles': PACIFIC,
+  'America/Vancouver': PACIFIC,
+  'America/Anchorage': {
+    yealinkOffset: '-9',
+    yealinkName: 'United States-Alaska Time',
+    posix: `AKST9AKDT,${US_DST}`,
+  },
+  'Pacific/Honolulu': {
+    yealinkOffset: '-10',
+    yealinkName: 'United States-Hawaii-Aleutian',
+    posix: 'HST10',
+  },
+  'America/Halifax': {
+    yealinkOffset: '-4',
+    yealinkName: 'Canada(Atlantic Time)',
+    posix: `AST4ADT,${US_DST}`,
+  },
+  'America/St_Johns': {
+    yealinkOffset: '-3:30',
+    yealinkName: 'Canada-New Foundland(St.Johns)',
+    posix: `NST3:30NDT,${US_DST}`,
+  },
+  'Europe/London': {
+    yealinkOffset: '0',
+    yealinkName: 'United Kingdom(London)',
+    posix: 'GMT0BST,M3.5.0/1,M10.5.0',
+  },
+  UTC: UTC_PHONE_TZ,
+  'Etc/UTC': UTC_PHONE_TZ,
+};
+
+/** The phone settings for a zone, and whether it's really that zone (false = UTC fallback). */
+export function phoneTimezone(iana: string): PhoneTimezone & { supported: boolean } {
+  const tz = PHONE_TIMEZONES[iana];
+  return tz ? { ...tz, supported: true } : { ...UTC_PHONE_TZ, supported: false };
+}