feat: filter reported errors

[gabyx]

Proposed Changes

• Add sentinel wrapping with errorfilter.FitlerReportedErrors to reduce error chains.
  Used on status.go::Log.

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Further Comments

[Copilot]

Pull request overview

This PR introduces an “already reported” error sentinel and a filter to drop those sentinel-wrapped errors from the final CLI error output, aiming to reduce redundant/long error chains when errors have already been logged earlier in execution.

Changes:

• Add WrapAsReported / FilterAlreadyReported utilities (plus tests) to mark and filter “already reported” errors.
• Wrap Summary.allErrors after DAG summary logging, and filter the final CLI error before printing an error summary.
• Rename stack dequeue API (PopFront → PopBottom) and adjust BFS usage accordingly.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
pkg/errors/filter/drop.go	Implements sentinel wrapper + filtering logic over multierror trees.
pkg/errors/filter/drop_test.go	Adds tests for the filter behavior with nested and flat multierror inputs.
pkg/dag/status.go	Moves runner-status logging to an internal method and wraps Summary.allErrors as “already reported”.
pkg/dag/run.go	Uses summary.Log() and unexports executeNormal.
pkg/dag/run-concurrent.go	Uses summary.Log() and unexports executeConcurrent.
pkg/dag/execution-order.go	Updates BFS traversal to use PopBottom().
pkg/common/stack/stack.go	Adds Top()/Bottom() helpers and renames bottom-pop API to PopBottom().
pkg/common/stack/stack_test.go	Updates tests to match the new PopBottom() API.
pkg/cli/cmd/root/root.go	Removes ErrorSummary CLI/config setting.
pkg/cli/cli-impl.go	Filters already-reported errors before calling log.ErrorE(...).

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[codecov]

Codecov Report

❌ Patch coverage is 96.66667% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 67.59%. Comparing base (f1be3b9) to head (36a6e05).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/errors/filter/already-reported.go	95.12%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #70      +/-   ##
==========================================
+ Coverage   67.30%   67.59%   +0.29%     
==========================================
  Files         116      117       +1     
  Lines        5389     5435      +46     
==========================================
+ Hits         3627     3674      +47     
- Misses       1440     1441       +1     
+ Partials      322      320       -2     

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