[WIP] Fix Pomodoro pause/resume bug: timer and state machine do not progress after resume

[Copilot]

• Analyze repository structure and understand build system
• Review current pomodoro.c and timer.c implementations
• Identify the root cause of pause/resume bug
• Fix pomodoro_pause() to avoid redundant change_state() calls
• Fix pomodoro_resume() to avoid redundant change_state() calls
• Ensure remaining_ms synchronization with timer module
• Fix timer callback parameter naming conflict
• Fix change_state() calls to use correct duration units (seconds)
• Improve pomodoro_get_remaining_sec() to return live timer data
• Test the fix works correctly
• Validate no regression in start/reset/expired transitions

✅ Pomodoro Pause/Resume Bug Fixed

Problem Solved: The Pomodoro timer state machine now correctly handles pause/resume operations without corrupting remaining time or interfering with timer internals.

Key Changes Made:

1. Fixed pomodoro_pause():

• ❌ Before: change_state(PAUSED_STATE, timer_get_remaining()) corrupted remaining time
• ✅ After: Direct state management with remaining_ms = timer_get_remaining()

2. Fixed pomodoro_resume():

• ❌ Before: change_state() calls could interfere with timer state
• ✅ After: Direct state updates + timer_resume() for clean separation

3. Additional Improvements:

• Fixed variable naming conflict in on_timer_tick() callback
• Corrected all change_state() calls to use proper duration units (seconds)
• Enhanced pomodoro_get_remaining_sec() to return live timer data
• Ensured state callbacks are properly triggered during pause/resume

Testing Verification:

• ✅ Core pomodoro library builds successfully
• ✅ Integration tests pass for all pause/resume scenarios
• ✅ No regressions in start/reset/expired transitions
• ✅ Timer callbacks and state machine logic preserved
• ✅ Full application build compatibility maintained

Root Cause Eliminated:

The bug was caused by redundant change_state() calls that:

1. Corrupted remaining time by multiplying milliseconds by 1000
2. Could overwrite timer internal state during resume
3. Created synchronization issues between pomodoro and timer modules

The fix provides clean separation of concerns where the timer module handles timing and the pomodoro module handles state transitions.

This pull request was created as a result of the following prompt from Copilot chat.

Bug Fix: Pomodoro state machine fails after resume from pause

Currently, when the Pomodoro timer is paused during any session (WORK, SHORT_BREAK, LONG_BREAK) and then resumed, the timer does not continue progressing correctly. The state machine may not advance, and the timer callbacks may not be correctly restored. This is due to redundant use of change_state() and mis-synchronization between the global remaining_ms (in pomodoro.c) and the timer module's internal tracking.

Fix Plan:

• In pomodoro_pause():
  • Only update the Pomodoro state to PAUSED (WORK or BREAK), and fetch the correct remaining time from the timer.
  • Do not call change_state() with a new duration that could overwrite state/timer internals.
  • Pause the timer.
• In pomodoro_resume():
  • Only update the Pomodoro state to running (WORK or correct BREAK type), but do not reset the timer duration or callbacks.
  • Do not call change_state() with a duration; simply set the correct state and unpause the timer.
• Ensure that the timer resumes correctly from its stored remaining time.
• Remove redundant or conflicting assignments to remaining_ms during pause/resume.

Acceptance:

• Pausing in any session works, and resuming continues the timer and state transitions as normal.
• Timer ticks and state callbacks are restored properly after resume.
• No regression to start/reset/expired transitions.

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