fix/improve the matching between emitted timing event `Tag`s and corresponding detected sampled HW trigger edges in the picoscope block

[wirew0rm]

goal: implement a robust, (stand-alone) unit-testable synchronisation flow so that each timing block emitted (UTC-based) event is aligned with sample-based edges (if hw_trigger == true) or mapped to equivalent sample indices (otherwise, i.e. if hw_trigger == false). Ensure that expired or impossible-to-match events are gracefully expired, and store clock-offset metadata when a valid match is found.
General sliding window time-synchronisation strategy:

1. Extend Timing Event Structure
   * add local_time (uint64_t, nanoseconds since epoch, new default Tag definition) to each timing event Tag map referencing the earliest local clock when the event as been received from the timing receiver.
   * introduce trigger_meta_information::hw_trigger(bool) indicating whether the event is associated with a digital IO hardware trigger or not.
   * introduce trigger_meta_information::local_timing_clock_drift (uint64_t) storing the clock offset (in ns) between the tag source and local data stream.
2. Time-to-Sample Mapping
   * for each data chunk (arriving at known intervals), compute the chunk’s local time range from the sampling rate and local host clock.
   * match events (hw_trigger == true) to hardware edges by aligning their “Timing Tag Timestamp” with edges in the chunk.
   * for events with no hardware trigger, map the event/tag to the corresponding sample index by comparing the time-stamps and counting samples to the nearest known matched HW trigger or absolute time reference.
3. Edge Boundaries & Overlaps
   * overlapping triggers in the same sample range must be attached in sorted order (according to UTC/TAI receiver time) to that sample.
   * N.B. consider an overlap region or slightly enlarged chunk boundary so partial triggers are not lost.
4. Data Loss / Stale Events
   * mark subsequent data as resync needed if chunks are missing to prevent incorrect matching.
   * discard or expire old events when their local_time timestamp falls too far behind the current chunk’s local time (configurable limit based on polling/chunk size).
5. Clock Drift / Offset
   * track and periodically update local_timing_clock_drift to adjust for differences between the local clock and the timing tag source (i.e. poor-man's-clock-PLL).
   * events may be dropped or flagged for manual resynchronisation if mismatch is too large
6. Multiple Overlapping Triggers
   * allow multiple TimingEvents to match a single hardware edge if their UTC time-stamps lie within the same sample.
7. Testability and Composability
   * matcher logic must be standalone that accepts synthetic input events and sample data.
   * no direct hardware or chunk fetch calls inside the logic
8. Performance Constraints
   * typical event rates of up to ~1 kHz are exepced. Should be manageable w.r.t. using queue-based or list-based matching but should nevertheless be optimised. goal: 1kHz trigger rate, ~250 MS/s sample rates, worst-case latency << 100 ms (for the digitizer block should probably < 10 ms to account for other delays/uncertainties in the chain).
9. Additional Corner Cases to be considered:
   * multiple tags per single edge (overlapping triggers).
   * fewer or more edges than tags.
   * tags arriving too late (chunk already processed).
   * large drift and time-offsets between tag timestamps and local clock.
   * missing chunks causing partial or mismatched data.