chore: remove old Hugo docs generation

[dangrondahl]

Summary

• Remove the docs.kosli.com/ Hugo site directory (239 tracked files)
• Remove old doc publishing workflows (publish_docs.yml, publish_branch_docs.yml)
• Remove docs-gen job from release.yml (the docs-repo-dispatch job is kept — Mintlify still uses it)
• Remove Makefile targets (cli-docs, legacy-ref-docs, hugo, hugo-local, test_docs, check-links, generate-json-metadata) and associated scripts
• Remove Hugo formatter (internal/docgen/hugo.go), make Mintlify the default and only doc format
• Clean up references in .gitignore, .clear-files, .htmltest.yml, README, dev-guide, and release-guide
• Remove Hugo helm-docs output line from helm-chart.yml (chart README output is kept)

Documentation is now fully maintained in kosli-dev/docs via Mintlify.

Closes kosli-dev/docs#42

Test plan

• go build ./cmd/kosli/ succeeds
• go test ./internal/docgen/... passes
• CI passes (lint, integration tests)

[claude]

Claude finished @dangrondahl's task in 2m 22s —— View job

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PR Review: Remove old Hugo docs generation

• Run static analysis (build, vet, mod tidy)
• Review modified files for correctness
• Review deleted files for completeness
• Check for leftover Hugo references
• Post review summary

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Static Analysis

All three checks pass cleanly:

• go build ./... — compiles successfully
• go vet ./... — no issues
• go mod tidy — no module drift

Review

This is a clean, well-structured removal. The PR systematically eliminates the Hugo docs pipeline across all layers — workflows, Makefile, Go code, test data, and documentation — without leaving dangling references. A few observations:

Things done well

1. Thorough cleanup — The slice-by-slice approach tracked in TODO.md ensured nothing was missed. All six slices are complete: workflows, release job, Makefile + scripts, site directory, Hugo formatter code, and cross-cutting references.

2. Tests updated correctly — generate_test.go assertions were updated from Hugo-specific checks ("# root child", "hint danger") to Mintlify equivalents (title: "root child", <Warning>). The compile-time interface check for HugoFormatter was removed. The docs_test.go correctly consolidated the Hugo and Mintlify test methods into single tests.

3. Release workflow dependency chain — docs-gen was cleanly removed from both the job definition and the needs list of the Slack notification job. The docs-repo-dispatch job (which Mintlify uses) is correctly preserved.

4. No leftover Hugo references in code — Searched for HugoFormatter, hugo, docs-gen, docs-main, .clear-files, and .htmltest across the codebase. The only remaining "Hugo" mentions are in internal/docgen/mintlify_test.go where they serve as negative assertions ("should NOT contain Hugo shortcode"), which is appropriate.

5. docs.kosli.com URL references are correct — Remaining references like https://docs.kosli.com/faq/... in flag descriptions point to the live documentation site, not the deleted Hugo directory. These are unaffected by this change.

Minor observations (non-blocking)

The --mintlify flag removal in docs.go and the simplification to always use MintlifyFormatter{} is the right call. The docsLongDesc still says "documentation in the following formats: Markdown" which is accurate — Mintlify output is still Markdown, so no issue there.

Summary

Clean PR — no issues found. The Hugo docs infrastructure is fully removed, the Mintlify path is the sole remaining doc format, and the release pipeline dependencies are consistent. LGTM.