chore(gitignore): ignore .webui_secret_key

[raullenchai]

Summary

The OpenWebUI session-secret file lives at the repo root (.webui_secret_key, 16 bytes) but wasn't in .gitignore. A previous git add -A on the perf/sampler PR briefly included it before the staging was reverted via git reset --mixed HEAD~1 + force-push.

Three-line addition under "Local secrets that must never be committed". Key rotated locally on 2026-06-09; the file is now properly ignored, so future git add -A sweeps can't re-include it.

Test plan

• git check-ignore -v .webui_secret_key reports .gitignore:71
• No new tracked files; only .gitignore modified

[github-actions]

PR #545 validation scorecard

Title: chore(gitignore): ignore .webui_secret_key
Author: raullenchai
Diff: 1 file(s), +3/-0 LOC, blast radius: medium

Verdict: DO NOT MERGE

step	status	summary	time
fetch	PASS	1 files, +3/-0 LOC, blast=medium	1.1s
test_plan_check	PASS	all 2 test-plan item(s) checked	0.0s
cl_description_quality	FAIL	PR title too short (2 words after prefix strip)	0.0s
codex_review	skip	codex CLI not found on PATH (install: npm i -g @openai/codex)	0.0s
supply_chain	PASS	no hooks touched, no suspicious patterns, deps clean	0.0s
lint	skip	skipped (gating predicate returned False)	0.0s
targeted_tests	skip	skipped (gating predicate returned False)	0.0s

Details

cl_description_quality — FAIL

Title (after stripping any conventional-commit prefix): ignore .webui_secret_key

Google eng-practices: 'Should be informative enough that future code searchers don't have to read your CL.' At least 3 meaningful words required. Examples: fix(routes): reject audio_url on text-only models vs fix: bug.