#12415: Code Quality: Add Strict Oxlint Configuration

Added strict oxlint configuration to enforce: - No unused variables - Strict null checks - No explicit any types - Prefer const over let - No var keyword - No duplicate imports Ensures better code quality and type safety moving forward <!-- greptile_comment --> <h2>Greptile Overview</h2> <h3>Greptile Summary</h3> This PR introduces a new `.oxlintrc` to enable stricter Oxlint rules (unused vars, const preference, duplicate imports, etc.) and extends `test/auto-reply.retry.test.ts` with cases intended to validate retry logging and max-attempt behavior for `deliverWebReply`. The retry-related tests currently don’t align with the `deliverWebReply` API/behavior in `src/web/auto-reply/deliver-reply.ts`: they omit a required `textLimit` param, pass an unsupported `maxRetries` param, and assert on `replyLogger.warn` for retries even though retries are logged via `logVerbose` instead. <h3>Confidence Score: 2/5</h3> - This PR is not safe to merge as-is because the newly added retry tests don’t match the current `deliverWebReply` API/behavior and should fail CI. - Confidence is reduced due to concrete test/API mismatches (missing required `textLimit`, unsupported `maxRetries`, and an assertion expecting retry warnings via `replyLogger.warn` that the implementation never emits). The Oxlint config itself is small, but the missing newline could also trip formatting checks. - test/auto-reply.retry.test.ts, .oxlintrc <!-- greptile_other_comments_section --> <!-- /greptile_comment -->