chore(all): Fix lint findings and ignore installed skill dirs

[enko]

What

Clears the Biome lint findings in project source and stops local Claude Code skill installs from polluting lint/git.

Lint fixes

• auth.ts — capture the auth pool in a local const so the create hook no longer needs a non-null assertion on the module-level let
• relationship-edit-form.svelte — guard getData() with an explicit null check instead of a non-null assertion
• url-row.test.ts — drop the unused fireEvent import

Skill dirs

• gitignore .claude/skills and .github/skills — these hold a locally installed skill (impeccable), not project source, and nothing in the repo depends on them. Biome's useIgnoreFile then skips them too, so no separate lint exclusion is needed.

Notes

• One pre-existing internal Biome crash on editor/inline-preview/inline-preview.ts (already in the ignore list) is unrelated and untouched.

Test

• npx biome lint . — clean
• pre-push gate (danger → check → type-check → test) passed locally

🤖 Generated with Claude Code

[github-actions]

Coverage Report

Test coverage is looking a little low for the files created or modified in this PR, perhaps we need to improve this.

Coverage threshold for statements (80%) not met: 0%
Coverage threshold for branches (80%) not met: 0%
Coverage threshold for functions (80%) not met: 0%
Coverage threshold for lines (80%) not met: 0%

Impacted Files	% Stmts	% Branch	% Funcs	% Lines	Uncovered Lines
apps/frontend/src/lib/ components/friends/ subresources/ relationship-edit-form.svelte	0	0	0	0	10, 23, 24, 25, 26, 27, 31, 32, 33, 35...	❌

Generated by 🚫 dangerJS against 09609e5