update lesson 4

Create .gitverse/workflows/html_js.yaml

adds pages and small updates

update lesson 4

update lesson 4

update lesson 5

chore: remove images

add_displacement

add_plots

add_offset

added_data_processing

feat(dynamic_6bar_linkage): add legend on plots

Merge branch 'diag_stat_bars' into for-merge

merge springs and static solver

Merge branch 'diag_stat_bars' of github.com:kutsjuice/Flexia into diag_stat_bars

feat(flexia): add time dependent forces

feat(6bar): add sinusoidal_func for bd4.forces

Merge remote-tracking branch 'origin/master'

feat(body): add time to body forces and build mass matrix separately

sync

implement parmech

fix(flexia): fix incorrect body boundaries for animation

fix(visualization): fix aspect ratio

feat(examples): add control to crankshaft example

fix(solvers): retore legacy cros! method

feat(theory): add natural frequencies description

add pics