Fix broken links to removed files in contributor docs

[no-hup]

Description

Three relative links in the contributor-facing docs point at files that no longer exist, so they 404 on GitHub. I found them while reading through the contributor docs, and each target was removed some time ago:

File	Dead link	Removed in
CONTRIBUTING.md	mathesar/api/STANDARDS.md	c73b663 — "remove mathesar/api/"
DEVELOPER_GUIDE.md	mathesar/api/README.md	c73b663 — "remove mathesar/api/"
mathesar_ui/README.md	mathesar/tests/integration/README.md	3e32316 — "remove disabled integration tests"

Changes

• CONTRIBUTING.md — the API standards doc has no successor now that mathesar/api/ is gone, so I dropped just that link and left the front end standards link intact.
• DEVELOPER_GUIDE.md — repointed the "API guide" link to the published API docs at https://docs.mathesar.org/latest/api/, which now covers API usage.
• mathesar_ui/README.md — removed the "Integration tests" subsection, since the integration tests it pointed at were removed as disabled.

Docs only; no code or behavior changes. After this, every relative link in the repo's markdown (outside docs/, which mkdocs resolves separately) resolves to a file that exists.

Question for reviewers

db/sql/STANDARDS.md does still exist. Would you like it linked from that CONTRIBUTING.md line in place of the removed API standards, e.g. "follow our front end code standards and SQL code standards where applicable"? Happy to add it if so — I left it out to keep the change strictly a fix.

Summary by CodeRabbit

• Documentation
  • Updated contribution guidance to reference the applicable front-end coding standards.
  • Updated the developer guide to link to the official online API documentation.
  • Simplified the front-end testing documentation by removing the integration testing section.

[coderabbitai]

📝 Walkthrough

Walkthrough

Updated repository documentation to reference front-end standards, link to the official API documentation, and remove the UI integration-test documentation subsection.

Changes

Documentation guidance

Layer / File(s)	Summary
Documentation reference updates CONTRIBUTING.md, DEVELOPER_GUIDE.md, mathesar_ui/README.md	Contribution guidance now references front-end standards only, the API section links to the official API documentation, and the UI testing section no longer includes integration-test documentation.

Estimated code review effort: 1 (Trivial) | ~2 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the documentation-only fix for broken links and removed references in contributor-facing docs.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

_{Comment @coderabbitai help to get the list of available commands.}

[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@CONTRIBUTING.md`:
- Line 43: Update the wording in CONTRIBUTING.md to hyphenate “front-end” in the
referenced code standards description, leaving the link and surrounding text
unchanged.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 83c93bb8-6e61-4e62-9ce1-3e15c3754482

📥 Commits

Reviewing files that changed from the base of the PR and between 0c05987 and 3931d73.

📒 Files selected for processing (3)

• CONTRIBUTING.md
• DEVELOPER_GUIDE.md
• mathesar_ui/README.md

💤 Files with no reviewable changes (1)

• mathesar_ui/README.md

[no-hup]

Friendly ping on this one — CI is green and it's still mergeable. It's a small docs-only change removing links to files that no longer exist, so it should be a quick look whenever someone has a moment. Happy to rebase if it's gone stale.