feat: update course for Riga in November

[marlon-tobaben]

Gets the course ready for Riga and fixes some small things in modules 02, 03, 05 and 08. Should close #37.

What's done

Across several modules:

• Updated the top README with the Riga location, the Nov 25–26 2026 dates, and a
  link to the rendered material.
• Replaced the old module use ... + module load lumi-aif-singularity-bindings
  with module load Local-LAIF lumi-aif-singularity-bindings (modules 03, 04,
  07, 08, 09).

Per module:

• 02: setup now points at /scratch; generation example uses
  max_new_tokens to match the docs below it; fixed a few typos.
• 03: explained why the job only gets 15 minutes (it's meant to time out
  before the approx 30 min run finishes, which sets up the checkpoint exercise). This closes Day 01 part 03 - recommended job duration is insufficient #35; fixed
  the slurm log path; swapped the hardcoded 50256 pad token for
  tokenizer.eos_token_id.
• 05: fixed the ubutnu_tree.def link text.
• 08: cleaned up whitespace in with_cpu_bindings/run_torchrun.sh.

What's left

• The old project number project_465002757 needs to be updated
• The AI_workshop_Day1/AI_workshop_Day2 might need to be tested
• Potentially update to newer container