Precision chime timing and BBC pips support

[heath-toby]

Summary

When auto-announce is set to "Speech and sound", chime sounds previously started playing at the minute boundary (:00), meaning the spoken time didn't arrive until several seconds later. This PR makes chimes start early so they finish at :00, with speech announcing the live current time immediately after — just like a broadcast time signal.

What changed

• Precision lead-in timing (clockHandler.py): The Clock class now calculates each chime's WAV duration and begins playback that many seconds before the minute boundary. Speech is deferred via wx.CallLater and reads datetime.now() at the moment it fires, so the announced time is always the true current time.
• BBC pips (clock_cuckoo7.wav): Receives dedicated handling. The file contains five short pips followed by a sixth long pip. Rather than aligning the end of the file with :00, the code aligns the onset of the sixth pip (at 5.22 s) with the boundary, faithfully reproducing a broadcast-style time signal. Speech fires with the sixth pip.
• Sound-only mode: BBC pips retains its precision timing (sixth pip on :00). All other chime sounds simply play at :00, as before.
• Speech-only mode: Unchanged — speaks the time at :00 with no chime.
• NVDA 2024.2+ compatibility (formats.py): Added safeGetTimeFormatEx and safeGetDateFormatEx wrappers that normalise None → 0 for the flags parameter, since newer ctypes no longer accepts None for DWORD arguments. Date display format building is also wrapped to prevent import-time crashes from locale or API changes.

How it works

Mode	Non-BBC chimes	BBC pips (clock_cuckoo7)
Speech + sound	Chime finishes at :00, speech immediately after	6th pip lands on :00, speech fires with it
Sound only	Plays at :00	6th pip lands on :00
Speech only	Speaks at :00	Speaks at :00

Files changed

• addon/globalPlugins/clock/clockHandler.py — precision timing logic, BBC pips handling, live time announcement
• addon/globalPlugins/clock/formats.py — safe wrappers for NVDA 2024.2+ ctypes compatibility
• readme.md — documented precision timing behaviour in the configuration section
• changelog.md — added entry for this release

Test plan

• Set auto-announce to "Speech and sound" with any non-BBC chime → chime should finish right on :00 and speech should follow immediately
• Set chime to clock_cuckoo7 (BBC pips) with "Speech and sound" → five short pips then the sixth long pip on :00, speech fires with the sixth pip
• Set to "Sound only" with BBC pips → sixth pip on :00, no speech
• Set to "Sound only" with any other chime → plays at :00, no speech
• Set to "Speech only" → speaks at :00, no chime
• Verify quiet hours still suppress all announcements
• Verify separate hour/intermediate chime selection still works
• Test on NVDA 2024.2+ to confirm no ctypes errors from formats.py

🤖 Generated with Claude Code

[zstanecic]

@heath-toby have you tested this?