[TASK] ci: enforce gofmt in the lint pipeline

[Aravinda-HWK]

What needs to be done?

Description

Our CI lint job (.github/workflows/linters.yaml) runs golangci-lint but does not fail on gofmt violations. In golangci-lint v2, formatters such as gofmt and gofumpt are opt-in, and there is currently no .golangci.yml configuration in the repository enabling them. As a result, unformatted Go code can pass CI.

This was observed in PR #286, where extractAllHeaders in internal/delivery/parser/parser.go was committed with non-gofmt indentation and the lint job still passed.

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Expected Behavior

CI should fail whenever any committed .go file is not formatted with gofmt.

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Steps to Reproduce

1. Introduce a gofmt violation (for example, remove leading tabs from several lines inside a function).
2. Push the change or open a PR.
3. Observe that the lint job passes even though:

gofmt -l .

reports the affected file.

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Proposed Solution

Option A — Dedicated gofmt Check (Recommended)

Add an explicit formatting check step to the golangci job in linters.yaml:

- name: gofmt check
  run: |
    unformatted=$(gofmt -l .)
    if [ -n "$unformatted" ]; then
      echo "::error::The following files are not gofmt-formatted:"
      echo "$unformatted"
      exit 1
    fi

Advantages:

• Simple and explicit.
• Independent of golangci-lint configuration changes.
• Easy to understand and maintain.

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Option B — Enable gofmt in golangci-lint v2

Add a .golangci.yml file at the repository root:

version: "2"

formatters:
  enable:
    - gofmt

Ensure CI runs golangci-lint with --fix=false so formatting issues are reported rather than automatically fixed.

Advantages:

• Keeps all linting and formatting checks centralized in a single tool.

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Acceptance Criteria

• A PR containing a gofmt violation fails the lint pipeline.
• gofmt -l . returns no output on main.
• The chosen approach is documented in the contributing guide or PR checklist (optional).

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Notes

Option A is recommended for clarity and to avoid relying on golangci-lint formatter configuration semantics. Option B is also valid if the project prefers keeping all code quality checks within golangci-lint.