Fix perf runner json

[Chandanydv1234]

Previously after the initial run the report was being over written every single execution. This meant loosing the older record data.
This PR modifies the script to store all the performance records and maintain a complete history of every single execution.
Changes made:-

1. Storing as a list of dicts instead of a single dictionary ensuring every single execution report can be appended to the list. Raw appending of dictionaries would create multiple separate json elements, which breaks the file as two json elements cannot be present.
2. Added safety checks in save_results to prevent FileNotFoundError and empty file crashes.
   3.Retrieves the last run (data[-1]) in load_results for the threshold comparison.
   4.Enables backward compatibility for the old dictionary formatted reports to automatically wrap them inside a list.

#2 Changes Made:-

1. instead of appending to JSON list, reports are now being updated individually, on the basis of phase, in csv format. and also implemented yearly roll over logic, whenever year changes the past report get's archived in the past year's report(eg - train_report_2025.csv) and then starts a fresh file.
2. Added a python script for plotting the reports. it reads all the reports dynamically ( *reports.csv). It compares run duration over time.
3. The generated chart is embedded in readme as png. as performance_chart.png
4. all of this automated using GitHub action. It automatically executes the plotting script using the updated csv and commits the new graph back to repo.

#3 Changes Made:-

1. Now ploting multiple datasets on the same chart dynamically, styling each dataset with unique lines (solid/dashed) and symbols (circles/triangles).
2. displaying PC Specs (dynamically parsed from the latest JSON report), Data Specs (parsed from the active config), and a Run Summary (aggregate averages, best times, and ratios).
3. Made some ui changes to better align with the default Zingg.ai theme. Switched to dark theme. added shaded gradients under the curve.
4. Displays the runtime at each point.

[sonalgoyal]

can you make this into a csv file? I dont want json.

[sonalgoyal]

can u send me the pr against oss action and not here. this is not the place we run our actions

[sonalgoyal]

please clear out dummy configs

[sonalgoyal]

please move all stuff to the script, leave only running part and passing params in action in respective code repors of oss and ent