fix: replace git hash with build number in UI footer

[Ma77Ball]

What changes were proposed in this PR?

• Replaced frontend/git-version.js with frontend/build-version.js, which uses build-number-generator to stamp a version + timestamp build number instead of shelling out to git describe.
• Swapped the git-describe devDependency for build-number-generator, and pointed the postinstall script at the new file.
• Simplified src/environments/version.ts schema to { buildNumber, version }, since the old git-describe output fields had a single consumer.
• Renamed DashboardComponent.gitCommitHash to buildNumber, updated the footer label to Build:, and renamed the #git-commit-id CSS id to #build-number.

Any related issues, documentation, or discussions?

N/A

How was this PR tested?

• Ran node build-version.js directly and confirmed it wrote a valid version.ts with the new buildNumber field.

Was this PR authored or co-authored using generative AI tooling?

Co-authored with Claude Opus 4.7 in compliance with ASF

[codecov-commenter]

Codecov Report

❌ Patch coverage is 55.55556% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 43.34%. Comparing base (bf2f92c) to head (d2502d3).

Files with missing lines	Patch %	Lines
...che/texera/web/service/WorkflowEmailNotifier.scala	0.00%	1 Missing ⚠️
...ent/admin/execution/admin-execution.component.html	0.00%	1 Missing ⚠️
...src/app/dashboard/component/dashboard.component.ts	0.00%	0 Missing and 1 partial ⚠️
...ponent/user/share-access/share-access.component.ts	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #5152      +/-   ##
============================================
- Coverage     43.35%   43.34%   -0.01%     
  Complexity     2212     2212              
============================================
  Files          1049     1049              
  Lines         40560    40556       -4     
  Branches       4322     4320       -2     
============================================
- Hits          17583    17579       -4     
  Misses        21886    21886              
  Partials       1091     1091              

Flag	Coverage Δ		*Carryforward flag
access-control-service	39.53% <ø> (ø)		Carriedforward from dbad080
agent-service	33.76% <ø> (ø)		Carriedforward from dbad080
amber	43.81% <80.00%> (-0.01%)	⬇️
computing-unit-managing-service	0.00% <ø> (ø)		Carriedforward from dbad080
config-service	0.00% <ø> (ø)		Carriedforward from dbad080
file-service	32.18% <ø> (ø)		Carriedforward from dbad080
frontend	34.60% <25.00%> (-0.01%)	⬇️	Carriedforward from dbad080
python	90.50% <ø> (ø)		Carriedforward from dbad080
workflow-compiling-service	56.81% <ø> (ø)		Carriedforward from dbad080

*This pull request uses carry forward flags. Click here to find out more.

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