CI: Reduce Action runs via trigger fix, concurrency, path filtering, and pip caching

[zrgt]

Summary

The current CI workflow triggers too many unnecessary Action runs. Four issues identified:

Problem 1 — Double Triggers (~50% run reduction)

on: [push, pull_request] causes every PR commit to trigger two runs (one for push, one for pull_request).

Fix:

on:
  push:
    branches: [develop, main]
  pull_request:

Problem 2 — No Concurrency / Cancel

Rapid successive commits cause all queued runs to complete, wasting runner minutes.

Fix — top-level in ci.yml:

concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

Problem 3 — No Path Filtering

A change in server/ still triggers all SDK and compliance-tool jobs.

Fix — per job with paths filter:

# sdk jobs
on:
  push:
    paths:
      - 'sdk/**'
      - '.github/workflows/ci.yml'

# compliance-tool jobs
on:
  push:
    paths:
      - 'compliance_tool/**'
      - 'sdk/**'

# server jobs
on:
  push:
    paths:
      - 'server/**'
      - 'sdk/**'

Note: path filtering at job level requires either separate workflow files per package or use of jobs.<job>.if with github.event.head_commit path checks.

Problem 4 — No pip Caching

All 12 jobs install dependencies from scratch on every run.

Fix — add cache: 'pip' to every actions/setup-python step:

- uses: actions/setup-python@v5
  with:
    python-version: ${{ env.X_PYTHON_MIN_VERSION }}
    cache: 'pip'

Impact Summary

#	Problem	Impact	Effort
1	Double triggers	~50% fewer runs	Low
2	No concurrency/cancel	Eliminates waste on rapid pushes	Low
3	No path filtering	Skips irrelevant jobs	Medium
4	No pip caching	Faster runs	Low

Recommendation: Fix problems 1 and 2 first — immediate impact, zero risk.