fix: simplify docker build process in ci

[VGau]

This PR implements issue(s) #

Checklist

• I wrote new tests for my new core changes.
• I have successfully ran tests, style checker and build against my new changes locally.
• I have informed the team of any breaking changes if there are any.

---

Note

Medium Risk
Changes CI control flow for building/pushing and the images used in E2E runs; misconfiguration could cause tests to run against stale develop images or skip needed builds.

Overview
Tightens CI image build conditions in build-and-publish.yml so coordinator/prover/postman/transaction-exclusion-api builds only happen when the service changed, or when push_image is enabled and the image still needs tagging.

Makes reuse-check-images-tags-and-push.yml more robust by defaulting image_tagged_* outputs to 'false' and only checking for existing tags on main.

Updates reuse-run-e2e-tests.yml to load Docker images from build artifacts when present, otherwise pull :develop for unchanged services, and sets per-service *_TAG env vars accordingly (instead of always using the commit tag).

^{Written by Cursor Bugbot for commit 557b90c. This will update automatically on new commits. Configure here.}

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 61.17%. Comparing base (0d5cce9) to head (557b90c).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #2367      +/-   ##
============================================
+ Coverage     61.13%   61.17%   +0.03%     
- Complexity     1626     1628       +2     
============================================
  Files           436      436              
  Lines         17362    17362              
  Branches       1908     1908              
============================================
+ Hits          10615    10621       +6     
+ Misses         6088     6083       -5     
+ Partials        659      658       -1     

Flag	Coverage Δ		*Carryforward flag
hardhat	97.89% <ø> (ø)		Carriedforward from 8969016
kotlin	56.90% <ø> (+0.03%)	⬆️

*This pull request uses carry forward flags. Click here to find out more.
see 2 files with indirect coverage changes

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Cursor Bugbot has reviewed your changes and found 1 potential issue.